The Bug:
Players' capes detach from their bodies when moving.
This issue was not present in 1.21.1 and was first introduced in 24w33a.
Steps to Reproduce:
Ensure that you have a cape enabled.
Begin sprint flying, enter third person, look directly downard, and look at how the cape is positioned.
Observed Behavior:
Players' capes detach from their bodies when moving.
Expected Behavior:
Players' capes would not detach from their bodies when moving.
Can confirm.