I can also confirm the issue happening on 20w49a - when trying to make pistons facing up via flatworld preset, no matter what I try, the preset gets reset to default one.
I don't think that this bug report is valid, since the crash happened on modified version of Minecraft, according to the provided crash log. You may need to report the issue to the creator of the affected mod instead of using official bug tracker to do so.
I've tested this in 1.18.2 and I can confirm that the kick does occur in this version. The reason why this doesn't occur with cheats enabled is the fact that the user is granted operator status when cheats are enabled while the world is loaded. With cheats disabled, the player won't be granted operator status upon loading the world. Operator has immunity from the built-in anti spam feature of the server.
I can also confirm the issue happening on 20w49a - when trying to make pistons facing up via flatworld preset, no matter what I try, the preset gets reset to default one.
I don't think that this bug report is valid, since the crash happened on modified version of Minecraft, according to the provided crash log. You may need to report the issue to the creator of the affected mod instead of using official bug tracker to do so.
I've tested this in 1.18.2 and I can confirm that the kick does occur in this version. The reason why this doesn't occur with cheats enabled is the fact that the user is granted operator status when cheats are enabled while the world is loaded. With cheats disabled, the player won't be granted operator status upon loading the world. Operator has immunity from the built-in anti spam feature of the server.