I'm sorry, I got the idea that you had set the hair up as dynamic.  If the skirt is the only object that has been Clothified, then I think your problem is one of two things:

1. There may be some geometry for the skirt that is actually inside the character's body, or intersecting itself, and is getting squirted out of the head eventually through bad luck;
2. You have a bugged version of V4 and need to download the updated version, install it, and run the "Update V4" script.

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