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.

You may be right. It looks like the ears have something to do with it. But P7 ran the simulation ok, so something must have changed in the behaviour of posers clothroom