iAvatar did not work there for a reason (and it probably told you there explicitly why) -That is animated morphs do not support bones deformation.
But when you pushed a mesh only morph with OBJ, it sort of worked… until you start animate where original bones no longer properly positioned to deform the mesh correctly.
We keep asking RL to support bones scaling for animated morphs, but then I wonder if any other app would support such morphs animation on timeline…