Pistons fire if block 2 above is powered
If the block 2 blocks above either a sticky piston or a regular piston is powered, the piston will extend. This occurs regardless of any block orientations (Piston/Lever/RS Torch) or the block being powered. If a piston receives an update and the block 2 above is powered, the piston will extend. If the block 2 above is removed and the piston is updated, the piston will retract. Redstone torches and observers 2 blocks above, however, will be able to update pistons on their own.
This works regardless of gamemode.
Environment
Windows 10, Java Version 8 Build 181
Created Issue:
Pistons fire if block 2 above is powered
If the block 2 blocks above either a sticky piston or a regular piston is powered, the piston will extend. This occurs regardless of any block orientations (Piston/Lever/RS Torch) or the block being powered. If a piston receives an update and the block 2 above is powered, the piston will extend. If the block 2 above is removed and the piston is updated, the piston will retract. Redstone Torches 2 blocks above, however, will be able to update pistons on their own.
Environment
Windows 10, Java Version 8 Build 181
If the block 2 blocks above either a sticky piston or a regular piston is powered, the piston will extend. This occurs regardless of any block orientations (Piston/Lever/RS Torch) or the block being powered. If a piston receives an update and the block 2 above is powered, the piston will extend. If the block 2 above is removed and the piston is updated, the piston will retract. Redstone Torches 2 blocks above, however, will be able to update pistons on their own.
This works regardless of gamemode.
If the block 2 blocks above either a sticky piston or a regular piston is powered, the piston will extend. This occurs regardless of any block orientations (Piston/Lever/RS Torch) or the block being powered. If a piston receives an update and the block 2 above is powered, the piston will extend. If the block 2 above is removed and the piston is updated, the piston will retract. Redstone
Torches 2 blocks above, however, will be able to update pistons on their own.
This works regardless of gamemode.
If the block 2 blocks above either a sticky piston or a regular piston is powered, the piston will extend. This occurs regardless of any block orientations (Piston/Lever/RS Torch) or the block being powered. If a piston receives an update and the block 2 above is powered, the piston will extend. If the block 2 above is removed and the piston is updated, the piston will retract. Redstone torches and observers 2 blocks above, however, will be able to update pistons on their own.
This works regardless of gamemode.

Thank you for your report!
We're actually already tracking this issue in
MC-108, so I resolved and linked this ticket as a duplicate.However, that ticket has already been resolved. Depending on the resolution, that can mean that it either will be fixed in the next version, or that it is not considered a bug and won't be fixed.
If you haven't already, you might like to make use of the search feature in the future to see if the issue has already been reported.
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