Taking damage while gliding applies knockback

The bug

When flying with elytra you can use arrows (or better healing arrows) and a Punch II bow in order to fly forever.

To reproduce

1. Get a Punch II bow and (healing) arrows
2. When you want to go higher, try to hit yourself with an arrow to get an high boost

Expected Behavior:

The expected behavior would be that you are not able to receive knockback when gliding with elytra.