MC-134920Channeling doesn't affect mobs standing on some non-full blocks and in boats/minecarts
The Bug:
Channeling doesn't affect mobs in some circumstances, here's a list of what i tested:
| soul sand | not struck by lightning bolt |
| snow | not struck if snow layers is 8 |
| Mob in a boat | not struck by lightning bolt. This doesn't affect passive mobs. |
| Mob in a minecart | not struck by lightning bolt. This doesn't affect passive mobs. |
| Honey block | not struck by lightning bolt |
| Inside a cobweb | not struck by lightning bolt |
| Inside lava | not struck by lightning bolt |
| Inside water | not struck by lightning bolt |
| Inside Powder Snow | not struck by lightning bolt |
Note: Mobs riding horses are not affected.
Linked Issues
![[Mod] Avoma](../../../data/avatars/users/86198.png){kind=small}
- Unresolved
TheGabro
Wit Uta- 22
- 9
- Confirmed
Low- Gameplay
- Entities
- channeling mob
1.13 - 25w03a
1.13 1.13.1 1.15.2 20w19a 20w20a 20w21a 20w22a 1.16-pre1 1.16-pre2 1.16-pre3 1.16-pre5 1.16-pre6 1.16-pre7 1.16-pre8 1.16 1.16.1 20w27a 20w28a 20w29a 20w30a 1.16.2-pre1 1.16.2 1.16.3 1.16.4-pre2 1.16.4 20w45a 20w46a 20w48a 20w49a 20w51a 21w03a 1.16.5 21w05a 21w07a 21w08b 21w10a 21w11a 21w13a 21w15a 21w16a 21w17a 1.17.1-pre1 1.17.1 21w39a 21w43a 1.18 1.18.1 1.18.2 22w11a 1.19-pre1 1.19 1.19.1 1.19.2 1.19.3 23w04a 1.19.4 23w16a 1.20.1 1.20.2 23w45a 1.20.4 24w11a 1.20.6 24w19b 1.21 1.21.1 24w39a 1.21.4 25w03a
Created Issue:
Channeling enchantment doesn't affect mobs standing on some non-full blocks
The bug has been tested during thunderstorm, in plains biome, using channeling tridents on pigs and villagers (for proper indication of strikes) on the following blocks:
Block Effect cobblestone struck by lightning bolt cobblestone slab not struck by lightning bolt cobblestone stairs struck by lightning bolt when standing on the upper half;
not struck if standing on the lower halfsoul sand not struck by lightning bolt farmland not struck by lightning bolt grass path not struck by lightning bolt glass struck by lightning bolt glass pane struck by lightning bolt oak fence struck by lightning bolt cobblestone wall struck by lightning bolt bed struck by lightning bolt end rod struck by lightning bolt snow struck by lightning bolt cake struck by lightning bolt Note: When even a tiny part of mob's hitbox is on a full block it gets struck by lightning bolt (found only in case of soul sand, farmland and grass path).
Environment
OS: Windows 7 Home Premium
Java version: 1.8.0_171 32bit
CPU: Intel Core i3
Graphics: AMD Mobility Radeon HD 5000 Series
The bug has been tested during thunderstorm, in plains biome, using channeling tridents on pigs and villagers (for proper indication of strikes) on the following blocks:
Block Effect cobblestone struck by lightning bolt cobblestone slab not struck by lightning bolt cobblestone stairs struck by lightning bolt when mob is standing on the upper half;
not struck if standing on the lower halfsoul sand not struck by lightning bolt farmland not struck by lightning bolt grass path not struck by lightning bolt glass struck by lightning bolt glass pane struck by lightning bolt oak fence struck by lightning bolt cobblestone wall struck by lightning bolt bed struck by lightning bolt end rod struck by lightning bolt snow struck by lightning bolt cake struck by lightning bolt Note: When even a tiny part of mob's hitbox is on a full block it gets struck by lightning bolt (found only in case of soul sand, farmland and grass path).
![[Mod] Asteraoth](../../../data/avatars/users/92886.png){kind=small}
The bug has been tested during thunderstorm, in plains biome, using channeling tridents on pigs and villagers (for proper indication of strikes) on the following blocks:
Block Effect cobblestone struck by lightning bolt cobblestoneslabnot struck by lightning bolt cobblestonestairsstruck by lightning bolt when mob is standing on the upper half;
not struck if standing on the lower halfsoul sand not struck by lightning bolt farmland not struck by lightning bolt grass path not struck by lightning bolt glass struck by lightning bolt glass pane struck by lightning bolt oak fence struck by lightning bolt cobblestone wall struck by lightning bolt bed struck by lightning bolt end rod struck by lightning bolt snow struck by lightning bolt cake struck by lightning bolt Note: When even a tiny part of mob's hitbox is on a full block it gets struck by lightning bolt (found only in case of soul sand, farmland and grass path).
The bug has been tested during thunderstorm, in plains biome, using channeling tridents on pigs and villagers (for proper indication of strikes) on the following blocks:
Block Effect cobblestone struck by lightning bolt slabs not struck by lightning bolt stairs struck by lightning bolt when mob is standing on the upper half;
not struck if standing on the lower halfsoul sand not struck by lightning bolt farmland not struck by lightning bolt grass path not struck by lightning bolt glass struck by lightning bolt glass pane struck by lightning bolt oak fence struck by lightning bolt cobblestone wall struck by lightning bolt bed struck by lightning bolt end rod struck by lightning bolt snow block and snow struck by lightning bolt; not struck if snow layers is 8 cake struck by lightning bolt Note: When even a tiny part of mob's hitbox is on a full block it gets struck by lightning bolt (found only in case of soul sand, farmland and grass path). Mobs in minecarts or on horses are struck but not when in a boat.
OS: Windows 7 Home Premium
Java version: 1.8.0_171 32bit
CPU: Intel Core i3
Graphics: AMD Mobility Radeon HD 5000 Series
Channelingenchantmentdoesn't affect mobs standing on some non-full blocksChanneling doesn't affect mobs standing on some non-full blocks and in boats
![[Mojang] Nathan Adams](../../../data/assets/gravatar/dinnerbone.png){kind=small}
![[Helper] Johnibur](../../../data/avatars/users/28381.png){kind=small}
![[Mod] Greymagic27](../../../data/avatars/users/92875.png){kind=small}
The bug has been tested during thunderstorm, in plains biome, using channeling tridents on pigs and villagers (for proper indication of strikes) on the following blocks:
BlockEffectcobblestone struck by lightning bolt slabs not struck by lightning bolt stairs struck by lightning bolt when mob is standing on the upper half;
not struck if standing on the lower halfsoul sand not struck by lightning bolt farmland not struck by lightning bolt grass path not struck by lightning bolt glassstruck by lightning bolt glass pane struck by lightning bolt oak fence struck by lightning bolt cobblestone wall struck by lightning bolt bed struck by lightning bolt end rod struck by lightning bolt snow block and snow struck by lightning bolt; not struck if snow layers is 8 cake struck by lightning bolt Note: When even a tiny part of mob's hitbox is on a full block it gets struck by lightning bolt (found only in case of soul sand, farmland and grass path). Mobs in minecarts or on horses are struck but not when in a boat.
The bug has been tested during thunderstorm, in plains biome, using channeling tridents on pigs and villagers (for proper indication of strikes) on the following blocks:
slabs not struck by lightning bolt stairs struck by lightning bolt when mob is standing on the upper half;
not struck if standing on the lower halfsoul sand not struck by lightning bolt farmland not struck by lightning bolt grass path not struck by lightning bolt snow block and snow struck by lightning bolt; not struck if snow layers is 8
Note: When even a tiny part of mob's hitbox is on a full block it gets struck by lightning bolt (found only in case of soul sand, farmland and grass path). Mobs in minecarts or on horses are struck but not when in a boat.
The bug has been tested during thunderstorm, in plains biome, using channeling tridents on pigs and villagers (for proper indication of strikes) on the following blocks:
slabs not struck by lightning bolt stairs struck by lightning bolt when mob is standing on the upper half;not struck if standing on the lower halfsoul sand not struck by lightning bolt farmland not struck by lightning bolt grass path not struck by lightning bolt snow block and snow struck by lightning bolt;not struck if snow layers is 8
Note: When even a tiny part of mob's hitbox is on a full block it gets struck by lightning bolt (found only in case of soul sand, farmland and grass path). Mobs in minecarts or on horses are struck but not when in a boat.
The bug has been tested during thunderstorm, in plains biome, using channeling tridents on pigs and villagers (for proper indication of strikes) on the following blocks:
slabsnot struck by lightning boltstairsstruck by lightning bolt when mob is standing on the upper half;
not struck if standing on the lower halfsoul sand not struck by lightning bolt farmlandnot struck by lightning boltgrass pathnot struck by lightning boltsnow block and snow not struck if snow layers is 8
Note: When even a tiny part of mob's hitbox is on a full block it gets struck by lightning bolt (found only in case of soul sand, farmland and grass path). Mobs in minecarts or on horses are struck but not when in a boat.
The bug has been tested during thunderstorm, in plains biome, using channeling tridents on pigs and villagers (for proper indication of strikes) on the following blocks:
slabsnot struck by lightning boltstairsstruck by lightning bolt when mob is standing on the upper half;
not struck if standing on the lower halfsoul sand not struck by lightning bolt farmlandnot struck by lightning boltgrass pathnot struck by lightning boltsnow block and snow not struck if snow layers is 8 Mob in a boat not struck by lightning bolt
Note: When even a tiny part of mob's hitbox is on a full block it gets struck by lightning bolt (found only in case of soul sand, farmland and grass path). Mobs in minecarts or on horses are struck but not when in a boat.
The bug has been tested during thunderstorm, in plains biome, using channeling tridents on pigs and villagers (for proper indication of strikes) on the following blocks:
slabsnot struck by lightning boltstairsstruck by lightning bolt when mob is standing on the upper half;
not struck if standing on the lower halfsoul sand not struck by lightning bolt farmlandnot struck by lightning boltgrass pathnot struck by lightning boltsnow block and snow not struck if snow layers is 8 Mob in a boat not struck by lightning bolt
Note: When even a tiny part of mob's hitbox is on a full block it gets struck by lightning bolt (found only in case of soul sand, farmland and grass path). Mobs in minecarts or on horses are
struck but not when in a boat.The bug has been tested during thunderstorm, in plains biome, using channeling tridents on pigs and villagers (for proper indication of strikes) on the following blocks:
slabsnot struck by lightning boltstairsstruck by lightning bolt when mob is standing on the upper half;
not struck if standing on the lower halfsoul sand not struck by lightning bolt farmlandnot struck by lightning boltgrass pathnot struck by lightning boltsnow block and snow not struck if snow layers is 8 Mob in a boat not struck by lightning bolt
Note: When even a tiny part of mob's hitbox is on a full block it gets struck by lightning bolt (found only in case of soul sand, farmland and grass path). Mobs in minecarts or on horses are not affected.
The bug has been tested during thunderstorm, in plains biome, using channeling tridents on pigs and villagers (for proper indication of strikes) on the following blocks:
slabsnot struck by lightning boltstairsstruck by lightning bolt when mob is standing on the upper half;
not struck if standing on the lower halfsoul sand not struck by lightning bolt farmlandnot struck by lightning boltgrass pathnot struck by lightning boltsnow block and snow not struck if snow layers is 8 Mob in a boat not struck by lightning bolt
Note: When even a tiny part of mob's hitbox is on a full block it gets struck by lightning bolt (found only in case of soul sand, farmland and grass path). Mobs in minecarts or
onhorses are not affected.The bug has been tested during thunderstorm, in plains biome, using channeling tridents on pigs and villagers (for proper indication of strikes) on the following blocks:
slabsnot struck by lightning boltstairsstruck by lightning bolt when mob is standing on the upper half;
not struck if standing on the lower halfsoul sand not struck by lightning bolt farmlandnot struck by lightning boltgrass pathnot struck by lightning boltsnow block and snow not struck if snow layers is 8 Mob in a boat not struck by lightning bolt
Note: When even a tiny part of mob's hitbox is on a full block it gets struck by lightning bolt (found only in case of soul sand, farmland and grass path). Mobs riding minecarts or horses are not affected.
The bug has been tested during thunderstorm, in plains biome, using channeling tridents on pigs and villagers (for proper indication of strikes) on the following blocks:
slabsnot struck by lightning boltstairsstruck by lightning bolt when mob is standing on the upper half;
not struck if standing on the lower halfsoul sand not struck by lightning bolt farmlandnot struck by lightning boltgrass pathnot struck by lightning boltsnow block and snow not struck if snow layers is 8 Mob in a boat not struck by lightning bolt Honey not struck by lightning bolt
Note: When even a tiny part of mob's hitbox is on a full block it gets struck by lightning bolt (found only in case of soul sand, farmland and grass path). Mobs riding minecarts or horses are not affected.
The bug has been tested during thunderstorm, in plains biome, using channeling tridents on pigs and villagers (for proper indication of strikes) on the following blocks:
slabsnot struck by lightning boltstairsstruck by lightning bolt when mob is standing on the upper half;
not struck if standing on the lower halfsoul sand not struck by lightning bolt farmlandnot struck by lightning boltgrass pathnot struck by lightning boltsnow block and snow not struck if snow layers is 8 Mob in a boat not struck by lightning bolt Honey block not struck by lightning bolt Inside a cobweb not struck by lightning bolt
Note: When even a tiny part of mob's hitbox is on a full block it gets struck by lightning bolt (found only in case of soul sand, farmland and grass path). Mobs riding minecarts or horses are not affected.
The bug has been tested during thunderstorm, in plains biome, using channeling tridents on pigs and villagers (for proper indication of strikes) on the following blocks:
slabsnot struck by lightning boltstairsstruck by lightning bolt when mob is standing on the upper half;
not struck if standing on the lower halfsoul sand not struck by lightning bolt farmlandnot struck by lightning boltgrass pathnot struck by lightning boltsnow block and snow not struck if snow layers is 8 Mob in a boat not struck by lightning bolt Honey block not struck by lightning bolt Inside a cobweb not struck by lightning bolt Inside lava not struck by lightning bolt
Note: When even a tiny part of mob's hitbox is on a full block it gets struck by lightning bolt (found only in case of soul sand, farmland and grass path). Mobs riding minecarts or horses are not affected.
The bug has been tested during thunderstorm, in plains biome, using channeling tridents on pigs and villagers (for proper indication of strikes) on the following blocks:
slabsnot struck by lightning boltstairsstruck by lightning bolt when mob is standing on the upper half;
not struck if standing on the lower halfsoul sand not struck by lightning bolt farmlandnot struck by lightning boltgrass pathnot struck by lightning boltsnow block and snow not struck if snow layers is 8 Mob in a boat not struck by lightning bolt Honey block not struck by lightning bolt Inside a cobweb not struck by lightning bolt Inside lava not struck by lightning bolt
Note: When even a tiny part of mob's hitbox is on a full block it gets struck by lightning bolt (found only in case of soul sand, farmland and grass path). Mobs riding minecarts or horses are not affected.
slabsnot struck by lightning boltstairsstruck by lightning bolt when mob is standing on the upper half;
not struck if standing on the lower halfsoul sand not struck by lightning bolt farmlandnot struck by lightning boltgrass pathnot struck by lightning boltsnow block and snow not struck if snow layers is 8 Mob in a boat not struck by lightning bolt Honey block not struck by lightning bolt Inside a cobweb not struck by lightning bolt Inside lava not struck by lightning bolt
Note: When even a tiny part of mob's hitbox is on a full block it gets struck by lightning bolt (found only in case of soul sand, farmland and grass path). Mobs riding minecarts or horses are not affected.
The Bug:
Channeling doesn't affect mobs
slabsnot struck by lightning boltstairsstruck by lightning bolt when mob is standing on the upper half;
not struck if standing on the lower halfsoul sand not struck by lightning bolt farmlandnot struck by lightning boltgrass pathnot struck by lightning boltsnow block and snow not struck if snow layers is 8 Mob in a boat not struck by lightning bolt Honey block not struck by lightning bolt Inside a cobweb not struck by lightning bolt Inside lava not struck by lightning bolt
Note: When even a tiny part of mob's hitbox is on a full block it gets struck by lightning bolt (found only in case of soul sand, farmland and grass path). Mobs riding minecarts or horses are not affected.
The Bug:
Channeling doesn't affect mobs
slabsnot struck by lightning boltstairsstruck by lightning bolt when mob is standing on the upper half;
not struck if standing on the lower halfsoul sand not struck by lightning bolt farmlandnot struck by lightning boltgrass pathnot struck by lightning boltsnow block and snow not struck if snow layers is 8 Mob in a boat not struck by lightning bolt Honey block not struck by lightning bolt Inside a cobweb not struck by lightning bolt Inside lava not struck by lightning bolt
Note: When even a tiny part of mob's hitbox is on a full block it gets struck by lightning bolt (found only in case of soul sand, farmland and grass path). Mobs riding minecarts or horses are not affected.
The Bug:
Channeling doesn't affect mobs in some circumstances, here's a list of what i tested:
slabsnot struck by lightning boltstairsstruck by lightning bolt when mob is standing on the upper half;
not struck if standing on the lower halfsoul sand not struck by lightning bolt farmlandnot struck by lightning boltgrass pathnot struck by lightning boltsnow block and snow not struck if snow layers is 8 Mob in a boat not struck by lightning bolt Honey block not struck by lightning bolt Inside a cobweb not struck by lightning bolt Inside lava not struck by lightning bolt
Note: When even a tiny part of mob's hitbox is on a full block it gets struck by lightning bolt (found only in case of soul sand, farmland and grass path). Mobs riding minecarts or horses are not affected.
image-2020-05-14-19-04-48-803.png
The Bug:
Channeling doesn't affect mobs in some circumstances, here's a list of what i tested:
slabsnot struck by lightning boltstairsstruck by lightning bolt when mob is standing on the upper half;
not struck if standing on the lower halfsoul sand not struck by lightning bolt farmlandnot struck by lightning boltgrass pathnot struck by lightning boltsnow block and snow not struck if snow layers is 8 Mob in a boat not struck by lightning bolt Honey blocknot struck by lightning bolt Inside a cobwebnot struck by lightning bolt Inside lavanot struck by lightning bolt
Note: When even a tiny part of mob's hitbox is on a full block it gets struck by lightning bolt (found only in case of soul sand, farmland and grass path). Mobs riding minecarts or horses are not affected.
The Bug:
Channeling doesn't affect mobs in some circumstances, here's a list of what i tested:
slabsnot struck by lightning boltstairsstruck by lightning bolt when mob is standing on the upper half;
not struck if standing on the lower halfsoul sand not struck by lightning bolt farmlandnot struck by lightning boltgrass pathnot struck by lightning boltsnow block and snow not struck if snow layers is 8 Mob in a boat not struck by lightning bolt. This doesn't affect passive mobs. Mob in a minecart not struck by lightning bolt. This doesn't affect passive mobs. Honey block not struck by lightning bolt Inside a cobweb not struck by lightning bolt Inside lava not struck by lightning bolt
Note: Mobs riding horses are not affected.
The Bug:
Channeling doesn't affect mobs in some circumstances, here's a list of what i tested:
slabsnot struck by lightning boltstairsstruck by lightning bolt when mob is standing on the upper half;
not struck if standing on the lower halfsoul sand not struck by lightning bolt farmlandnot struck by lightning boltgrass pathnot struck by lightning boltsnow block and snownot struck if snow layers is 8 Mob in a boat not struck by lightning bolt. This doesn't affect passive mobs. Mob in a minecart not struck by lightning bolt. This doesn't affect passive mobs. Honey block not struck by lightning bolt Inside a cobweb not struck by lightning bolt Inside lava not struck by lightning bolt
Note: Mobs riding horses are not affected.
The Bug:
Channeling doesn't affect mobs in some circumstances, here's a list of what i tested:
slabsnot struck by lightning boltstairsstruck by lightning bolt when mob is standing on the upper half;
not struck if standing on the lower halfsoul sand not struck by lightning bolt farmlandnot struck by lightning boltgrass pathnot struck by lightning boltsnow not struck if snow layers is 8 Mob in a boat not struck by lightning bolt. This doesn't affect passive mobs. Mob in a minecart not struck by lightning bolt. This doesn't affect passive mobs. Honey block not struck by lightning bolt Inside a cobweb not struck by lightning bolt Inside lava not struck by lightning bolt Inside water not struck by lightning bolt
Note: Mobs riding horses are not affected.
Channeling doesn't affect mobs standing on some non-full blocks and in boats/minecarts
![[Mojang] slicedlime](../../../data/assets/gravatar/slicedlime.jpeg){kind=small}
![[Mojang] Adrian Östergård](../../../data/assets/gravatar/nighter.jpeg){kind=small}
The Bug:
Channeling doesn't affect mobs in some circumstances, here's a list of what i tested:
slabsnot struck by lightning boltstairsstruck by lightning bolt when mob is standing on the upper half;
not struck if standing on the lower halfsoul sand not struck by lightning bolt farmlandnot struck by lightning boltgrass pathnot struck by lightning boltsnow not struck if snow layers is 8 Mob in a boat not struck by lightning bolt. This doesn't affect passive mobs. Mob in a minecart not struck by lightning bolt. This doesn't affect passive mobs. Honey block not struck by lightning bolt Inside a cobweb not struck by lightning bolt Inside lava not struck by lightning bolt Inside water not struck by lightning bolt Powder Snow not struck by lightning bolt
Note: Mobs riding horses are not affected.
![[Mod] LateLag](../../../data/avatars/users/92884.png){kind=small}
relates to
The Bug:
Channeling doesn't affect mobs in some circumstances, here's a list of what i tested:
slabsnot struck by lightning boltstairsstruck by lightning bolt when mob is standing on the upper half;
not struck if standing on the lower halfsoul sand not struck by lightning bolt farmlandnot struck by lightning boltgrass pathnot struck by lightning boltsnow not struck if snow layers is 8 Mob in a boat not struck by lightning bolt. This doesn't affect passive mobs. Mob in a minecart not struck by lightning bolt. This doesn't affect passive mobs. Honey block not struck by lightning bolt Inside a cobweb not struck by lightning bolt Inside lava not struck by lightning bolt Inside water not struck by lightning bolt Inside Powder Snow not struck by lightning bolt
Note: Mobs riding horses are not affected.
![[Mod] SPGoding](../../../data/avatars/users/44622.png){kind=small}
relates to
![[Mod] Michael Wobst](../../../data/avatars/users/37868.png){kind=small}
![[Mod] ampolive](../../../data/avatars/users/18949.svg){kind=small}
![[Mod] markderickson](../../../data/avatars/users/18946.svg){kind=small}
On what block did the creeper stand on? Does MC-134920 describe your issue?
Does MC-134920 describe your issue?
Duplicate of MC-134920
Can confirm in 21w11a. I wouldn't say this is a duplicate of MC-134920, however, it's related.
Justin Zheng, this is not a duplicate of MC-134920. See the above conversation.
![[Bot] Arisa](../../../data/avatars/users/43007.png){kind=small}
As owner of MC-134920 I have updated the description by adding powder snow. My ticket is just more generic than yours as it covers every blocks/entities affected, I don't know if this could be considered a duplicate or not.
Sounds like the thurderstorm is going to the top of the block only, but if the mob is slightly lower than that, it doesnt hit it
Doesn't really explain the glass panes, fences, beds, etc.
Can confirm.
I'm thinking maybe the game uses the lighting subroutine to check for sky access?
Apart from the boat the blocks where lightning doesn't strike seem to be the ones where F3 reports 0 light.
Boats on land do have 0 light though, and a boat in water possibly counts as being in water.
Boats in water only have 14 sky light which isn't full sky access.
Mobs in lava aren't struck by lightning either, also 14 sky light.
affects 20w18a
affects 20w19a
affects 20w20a
Can confirm in 21w05b.
also mobs in powder snow are not affected by channeling and mobs in minecarts/boats are now affected
Also channeling does not work on skeletons when riding a spider (skeleton jockeys), above a non-air block.
However it does work with any of the zombie baby varients riding a chicken, when a baby piglin is riding a baby hoglin, or zombified variants of each. Channeling works on striders riding striders, but not zombiefied piglins riding striders as well.
While the reporter has commented that channeling works if passive mobs are in a boat, it does not work if the mobs hitbox is within the ground while in a boat, such as with wandering traders, striders and villagers.
On the other hand, channeling does work, if hostile mobs are in a boat, but their entire hitbox is outside the ground, such as by centering a boat and removing the block under it, so that it is balanced above the ground.
It also doesnt work, if any part of the mobs hitbox, is within another block, such as when a falling block is dropped on it (aside from shulkers) or when a block is pushed into it (again, aside from shulkers)
Channeling does, however, does work when a mob is standing on a shulker(mob), boat, or if it is falling.
It seems as if, the times channeling doesn't work, is just due to collisions with blocks that cannot be moved through like usual. As stated in the bug report description, this includes water, lava, cobweb, honey block, powdered snow, soul sand. It also happens when a mob is sitting in some other mobs, in some cases, such as when the ridings mobs hitbox is going through the lower mobs hitbox into a block. Even 8 snow layers, acts as if it is a full block, such as it attaches to fences. But when going through the block, you are 0.125m lower than a full block, therefore colliding with the hitbox of the 8 snow layers.
My personal assumption, is the reason that channeling might not work with colliding blocks, could be because the game presumes that it is under a block when it is touching one. So, instead of checking 1 block above the payer, it is checking at the player's feet. Since the game does not produce lightning, when the mob is under a block, it decides to not.
So, the possible reasoning by commenter Eric Rowley, isn't entirely off-base, since it is likely that it is due to a check for sky access. Similarly, the idea by Mod Urielsalis, is not off base either, since quite often, when lower than a full block, you are in a block as well, although not all the time.
The solution to this would be to check above the player's head, rather than his feet. Unfortunately, due to mechanics like crouching under slabs, the player can be in the same block, as the block, but still be under it. So the way this would need to be done, is check directly above the player, by 1/16 meters (1 pixel) and go up from there.
Confirmed in 21w17a.
Can confirm in 1.17.1 Pre-release 1.
Can confirm in 1.17.1.
Can confirm in 1.18.1.
I would assume the cause of this bug (as well as MC-125773 and MC-217528) to be that Channeling checks for sky exposure at a mob's feet level. So when mobs are standing on non-full blocks that block sky light, their feet technically don't have sky access, therefore Channeling doesn't work. Similarly, when mobs are riding boats/minecarts, their hitboxes extend below the bottom of the vehicles, observable using F3 + B. Hopefully someone can do a code analysis on this, so my speculation can be confirmed.
Can confirm for 22w11a.
Can confirm in 1.19.
Can confirm in 1.19.2.
Can confirm in 1.19.4