Hello,

The issue is that capes stutter when strafing left or right with your A & D keys, whereas on 1.16 and below, the cape has had a smooth animation.

Video showing examples of the bug, and a version of Minecraft where the bug was not present:

Version 1.19.3 (Cape stutter present)
https://www.youtube.com/watch?v=9OTk8YNcfIQ

Version 1.12.2 (Cape issue not present)
https://www.youtube.com/watch?v=O30qOsweFDw