The Bug:
Capes occasionally jitter when moving and adjusting your rotation.
It appears that MC-127749 fixed a large portion of this problem, however, some remnants of it still remain.
Steps to Reproduce:
Ensure that you have a cape enabled, enter creative mode, and begin flying.
While moving forward and right at the same time, slowly adjust the horizontal rotation of your player and watch your cape closely as you do this.
Take note as to whether or not capes occasionally jitter when moving and adjusting your rotation.
Observed Behavior:
Capes occasionally jitter.
Expected Behavior:
Capes would not jitter.
Relates to or clones MC-127749. This problem was discovered thanks to @unknown's 23w05a update video.