In versions prior to 1.13, when a donkey or mule equipped with a chest walked, (whether autonomously or under player control) the chest would wobble. However, with the shift in mob rotation synchronization to align fully with the player in 1.13 (previously it was only partially synced), this characteristic feature seems to have been inadvertently removed.

Steps to Reproduce:

1. Summon/Spawn a donkey (or mule)

   /summon minecraft:donkey ~ ~ ~ {Tame:1b,SaddleItem:{count:1,id:"minecraft:saddle"},ChestedHorse:1b}
   

2. Mount it
3. Walk forward, in third-person view

Observed Behavior:

The chests do not wobble.

Expected Behavior:

The chests would wobble side-to-side just as in previous versions.

Screenshots/Videos:

Current Behavior:
NoWobble_24w09a_VideoEvidence.mp4

Previous Behavior:
WobblyChest_1.12.2_VideoDemo1.mp4

Bedrock edition:
0412.mp4

Notes:

As pointed out by EVGENSYPERPRO, and noted in their attached video, this is also a parity issue with bedrock.