I have looked at skirt and see that does happen with certain morphs.
It seems to be the ones that would be a V4 FBM, I have never used those on the skirt before.
The ones that are unique to skirt (e.g., Skirt_FullBack1) do not seem to have this problem.
The problem seems to happen in both P8 and PP2010.
For mean time, I am at loss to help.