When a player goes unconscious they will sometimes clip into a wall. Upon waking up they might be stuck. The same will probably happen with objects other than walls.
1.12 made going unconscious common so players will encounter this issue more frequently going forward.

Seems to happen more in tight spaces. Maybe the game is trying to prevent the player from clipping into one object and as a result the player gets pushed into another object.

You can sometimes unstuck people by throwing items under or on top of them. If an item lands under a player it will push them up and sometimes to the side as the player slides off the item. If the item lands on top of the player then it might start falling between the player and wall and push the player out.