Physics of custom capes do not match vanilla cape physics

[Remdrift]

Mod version - Fabric-1.21 v0.6.19a Minecraft version - 1.21.1 I tested this bug using only CustomPlayerModels and Fabric API.

The physics of custom capes created using "Add Parts" do not match vanilla capes. The custom capes stutter and move erratically. This is very noticeable when you are flying, moving quickly, or sprint-jumping.

Example:

https://github.com/user-attachments/assets/395a4fb8-481e-4889-b4a0-0e0d629c128d

[Phaxtolgia]

Huh. I knew something about them was off. Good to have a confirmation.