Player model stuck in flying position when gliding into water

The bug

While gliding into a body of water (or lava), your player model gets stuck in the gliding position and will be unable to get back in upright position, when you try to resurface on top of the water.

When you touch the top surface of a block, the "swimming" routine will end and put you back in upright position, and reset the situation. But this should also happen when you "surface" on the water, as this behaviour requires you to use the control for swimming upwards, which is not used for gliding to begin with, so the game should know you don't want to glide anymore.

How to reproduce

1. Put on some elytra

2. Take off with a rocket like you normally do

3. Dive into a reasonably deep body of water, trying to prevent touching any sea floor while underwater

4. Stop flying and press space to swim up to the surface
   ❌ Your body refuses to turn upright