The Bug:

Entities' limbs are incorrectly positioned for a brief second when entities are damaged while riding entities.

This issue did not occur in 1.21.1.

Steps to Reproduce:

1. Summon a tamed horse by using the command provided below.

   /summon minecraft:horse ~ ~ ~ {Tame:1b}

2. Switch to survival mode and begin riding the horse.
3. Damage yourself constantly by using the command provided below.

   /damage @s 1 minecraft:generic

4. Watch your arms closely as you receive damage.

Observed Behavior:

Entities' limbs are incorrectly positioned for a brief second.

Expected Behavior:

Entities' limbs would not be incorrectly positioned for a brief second.