If you jump while not flying right as you touch the ground, your player model will spin around 180 degrees (can only be seen rendered sometimes, it realigns extremely quickly) and then jump forward at higher than normal height and speed. This does not consume durability.

Steps to reproduce:

1. Equip an Elytra. For the sake of demonstration I was using a leather chest plate with the glider component.
2. Jump in the air, and then the exact moment before (and sort of right as) you hit the ground, press and hold the jump key to deploy the elytra. The player model will stutter and the player will do a kind of hop forward, launching them further and faster than a normal jump.

Expected outcome:

• The player model should not stutter, and the elytra should probably just not open that close to the ground. Either that or it should open and the player should hit the ground and then the elytra would close, which matches the behavior of previous versions.