When parrots ride on players' shoulders, they move downward when the player sneaks. If a non-parrot mob rides a player, though, their position does not adjust for sneaking.
- Install the attached behavior pack and apply it to a world.
- Summon a cat, then approach it. It should automatically ride the player.
- Sneak with the cat riding on you.
→ Its model does not adjust for the player sneaking, and remains stationary.