Shield transition animation is not showing again in Beta 1.18.10.21.

Steps to Reproduce:

1. Create a new world
2. Obtain a shield
3. Block with the shield
4. Observe the shield animation
5. Stop blocking with the shield, and then block again
6. Observe the shield animation

Observed Results:
The shield only transitions smoothly from the resting position to the blocking position when blocking for the first time.

Expected Results:
The shield should always transition smoothly from the resting position to the blocking position.