After importing this scene as an fbx the animation in the larger character's right leg goes bad.
(I've added annotations with the points and times.)
I've checked my local files on Maya and Motionbuilder and they playback with no issues. Joint rotation order seems good, but I tried changing it anyway. I've also tried exporting at 60 fps. Does the sketchfab player resample the animation data and apply a different joint rotation order?
Any help would be greatly appreciated.