When sailing on a shift with elytra, elytres flash

Summary:
When a player with elytres starts to swim without getting up from the shift, his elytres start blinking very strongly. On android, this works even if the player just decided to press the shift while swimming.

Steps to reproduce:

1. Put on your elytra.

2. Enter the water.

3. Start swimming.

4. Press shift (without stopping to swim).

Observed results:
Elyra starts to twitch.

Expected results:
Nothing should happen.

Video: