The Elytra animation only plays in 3rd person, not 1st person. This means the animation only update when you are looking for yourself.

Steps to Reproduce:

By gliding

1. Equip Elytra
2. Start gliding
3. Switch to 3rd person

By sneaking

1. Equip Elytra
2. Start sneaking
3. Switch to 3rd person then return to 1st person
4. Stop sneaking
5. Do same as step 3

Observed Results:

The Elytra animation only plays in 3rd person, not 1st person

Expected Results:

The Elytra animation should play in both 3rd person and 1st person