Point of vision can become unsynced with player model (Elytra)

1. Put elytra on.
2. Dig a 1*1*x row of blocks out of the ground.
3. Stand next to the entry.
4. Jump twice so that elytra gets activated and fly inside the row (you might have to sprint to not get pushed out again).
Result: The player model is two blocks high again as soon as player reaches the ground, but the hitbox stays one block high and it's actually possible to walk around in a one block high space. Shifting restores the hitbox, making you suffocate in a block.