The cr2 with animatable joint flag set had more weightmaps in the actor definition. If My memory is not playing tricks on me then there were more weightmaps than I expected, based on the joint definitions. When setting animatable to 1 with text editor, the flag looked set in the UI, but the teaching tool would not create dependencies for the actor. First I assumed one could not save this property in a cr2, but after clicking manually every joint to animatable it all worked and also was savable. Will investigate some more this evening.