Flying Vertex(s) glitching into space frequently when uploading models with animations - Bugs - Sketchfab Forum
How to import from Blender to SketchFab WITH textures/materials applied? - Bugs - Sketchfab Forum
Animation translating poorly between Blender and Sketchfab (using duplicates of meshes and keyframed scales to emulate visibility) - Support - Sketchfab Forum