Shield activation animation in first person on main hand is missing

Summary:
In version 1.16.210.58, the shield activation animation is gone. (first person)

Steps to Reproduce:

1. Take the shield into your main hand.
2. Sneak down to activate the shield.

Observed Results:
There is no shield activation animation when using main hand. (first person)

Expected Results:
The animation works fine.

 Video:

mcpe.mp4