Quote - I think that there can be any JMC magnet. Try craeate phantom head - head shape prop but less resolution. It really helps. V4 head has number of polygons on ears, lashes etc. Their normals have different directions and it can cause simulation errors.

I made a test with this, using the skullcap parented to the head for the simulation. Turns out that the hair's constrained group will not follow the skullcap unless the head is included in the simulation too.

It turns out that JoeBushido's cloth hair doesn't have this issue. It's a conforming item with the hair included as a prop which is then simulated. Why this works is beyond me though.