Metahuman Head and Body Merge Rig issue Cinema4d

I am trying to merge the head and body animations in Cinema 4D
so that I can export them as an FBX file for use in Marvelous Designer as motion. Although I know there are other ways to export animations, I specifically need to merge the head and body rigging for a project I am working on. However, after parenting the rigs of the head and body, I encountered an issue that I have attached. Do you have any ideas about what might be causing this problem? I’ve checked all the rig parenting, and everything looks fine on there.