The bug

If I have the levitation effect, get stuck on a ceiling and press shift, I get stuck in sneaking position (and move slow as a result). As I understand it, if I press shift while I have Levitation, the player becomes 1.5 blocks tall instead of 1.8, it moves higher up and when I let shift it has no space above its head to return to normal position and 1.8 height.

How to reproduce

Creative mode

1. Stand below a block
2. Give yourself levitation
3. When you get stuck at said block, press shift and let it.

You will see that you remain in crouching position.

Survival mode

The same, in order to get levitation go to an end city and get hit by a shulker.