Swimming backwards when in elytra flying mode flips player model upside down

The bug

When flying with an elytra you can dive into water and keep swimming with the wings spread. However when you try to go backwards while flying in water you start swimming upside down.

How to reproduce

1. Enter a world with enough water to swim around
2. Obtain an elytra and equip it
3. Start flying above water and fly into the water
4. Press "Walk backwards" move key
   → See the player model flip