This has happened as Viewports have crashed and most (From my experience and others) images, Viewports, parts of imported meshes, and imported textures are unable to be seen my players and developers. (I don’t know much about this situation but from what I am hearing this is what I have come up with. !DM me if I got something wrong!)
As mentioned in this post, it may have to do with whether the skinned MeshPart is a client-only (local) part vs. the part existing on the server (the local skinned MeshParts being the ones that do not appear).
This is not true, simply importing the custom skinned meshes will result in them not being rendered, whether on server or client. You can inspect this in studio: S15_Lola_IPose.fbx (639.2 KB) LolaS1StarterCharacter.rbxl (28.9 KB)