My guess off the top of my head is that since this mesh was created without skeleton data and has a 'Weights vertex channel' then its causing the error since it doesn't have 'access to the skeleton data'. However, this doesn't explain why the error isn't present on other similar meshes that have been created without a skeleton. I haven't had this issue come up before with any other fbx files in my entire project so I'm curious what is causing this error. I guess I'll learn more after I investigate.
