Hi, yeah for some reason in my notes I had put down to uncheck the morph targets box but you’re correct you need it checked. I have just managed to recreate your issue and also fix it, it appears to have to do with the rotation export options. I’m also reusing the original face mesh and duplicating it and then reimporting the face mesh with a new file, if the orientation isn’t correct it comes in deformed.
Before export from blender I rotate the mesh and armature 90 degrees so the face is facing the ground plane and my export settings are default;
-Z Forward
Y Up
And also untick apply modifiers in the geometry.
If you have no luck I will put together some screenshots and my process m. With this method you have to reassign the materials on import.