Skin turns 'Ruth' when taking off clothes

I'm not really sure where to look for an answer to this problem - it is a difficult one to search on, but I'm hoping soemone here might know what the problem is. I am really sorry if this is not the right place (as I only have a Basic SL account, I don't believe I can log a support ticket for this) - please let me know if I should be looking for a solution to this elsewhere.

My SL partner is having a problem where sometimes when she takes clothes off her av, the skin turns into what looks like the old 'Ruth' skin. It might just be her upper body, or lower, or it can be her whole body. Everyone can see this, so it is not just her & some problem with her video card. She tries all the usual things like clear cache, relog, rebake. Sometimes putting the clothes she just took off, back on, will bring the skin back... but taking the clothes off again makes the Ruth skin come back. I think if she goes into 'Appearance' her skin comes good, but it goes bad once she comes out. In all the time I spend with her, I have never once had a hint of this problem with my av.
This is driving her crazy, and stressing her out as we all want to look good in SL - particularly with our clothes off!! Seriously, though, she has a management type role, with lots of facing puplic & really needs her av looking good & not turning into the blob when she wants to change outfits!

Thanks.

Just to clarify - The av shape does not change, only the skin does. It turns into this pasty mess with very little detail. I'm guessing it is some sort of default skin.

Try a different skin?

when I saw the title of the thread I though the setting to ignore appearance packets (I forgot how it is called in the interface) to test ruthing might have been accidentally enabled, though now reading the additional details I dunno, are you sure somthing like a "tattoo" that is actually meant to be replace skin texture, isn't being removed and revealing the default skin underneath?