Since the latest update, you sometimes glitch into blocks when hit by a monster or player (possibly from general damage).
Note: This bug does not occur if you try to walk in a certain direction.
Linked issues
is duplicated by 17
relates to 4
Attachments
Comments 14
Potential related issue: mobs get pushed into blocks when taking damage from a trident killer and remain in the blocks.
Wiings: if you are referring to spiders being pushed out of a 2x2 trident killer (the kind where 4 pistons push the trident around in a circle, that issue is tracked MCPE-153431 and is unrelated to this one.
This is absolutely related to: MCPE-194370
It's actually the exact same issue: you receive knockback and get pushed into a position, but something prevents you from reaching that position. The same thing that causes MCPE-194370 is causing this issue as well.
The game forces you into the position where you would have ended up, had something not blocked you.
The only difference with this bug is that the block you're forced into pushes you back out — which, by itself, isn't a bug.
Relates to MCPE-190552