If the player is in the swimming mode and attempts to stand when under a top placed slab or trapdoor, they are not prevented from doing so. This causes the player to clip through said block as long as there aren't any blocks with collision above that one.
Original Description
when you slab put water under it and up swim
you are slab going to the top
Linked issues
is duplicated by 11
Attachments
Comments 4
The reproduction methods of this issue is being blocked by MCPE-98271 in the betas, as it is impossible to enter 1x1 areas with an elytra or swimming outright.
If you are in a non-beta version of the game, you don't have to worry about the other ticket. If you are in a beta, MCPE-98271 is affecting you.
YEP....