Choreographed didn't do it either. The constraints still won't follow the parented skullcap. :/ It also raises another problem, which is the rest of the body. It's a very long hair, so it needs to drape over arms, chest, back etc. If any V4 bodypart is selected, not just the head, the same weird thing happens.

SM is on the case at the moment trying to help figure out what's going on and finding a workaround, too.

 

Quote - Constrained groups do not works against props. You can make it choreographed.

Maybe it is a bug, but if there is any magnet different Poser version can select different way child props. Default setting should not include magnets o colliding group, but maybe P9 does not recognize it as a magnet.

Nevertheless I think that transparent prop resolve problem faster and easier then SM fix Poser. Moreover you can join hair strands and head phantom as a 1 prop (choreographed group)

sample