Off-hand shield has no blocking animation

When the shield is on the player's off-hand, and the player blocks an attack from another player, a mob, or a TNT explosion there is no blocking animation. See the comparison between the main hand shield and off hand shield blocking animation.

Steps to Reproduce:

1. Spawn a hostile mob

2. Equip a shield in your off-hand

3. Switch to Survival mode

4. Block an attack from the mob

Observed Results:
There is no blocking animation.

Expected Results:
There should be a blocking animation.

Videos: