I'm uploading a short sequence of a robot flying into a wall and falling. However, there seems to be an issue with my robot fly/fall sequence on Sketchfab as once he falls to the ground, his left leg stays up and the emission cylinder is no longer attached to that foot. The 'child of constraint' constraint is intact and correct throughout the whole sequence on Blender, and the leg is always in the correct position/angle too. I'm thinking this is occurring the export/upload phase?
Here are some photos of 'blender vs. sketchfab' and my export settings that I hope make the nature of this issue clearer.