Oh wow.....can this be validated?
I *almost* wish I had a copy just so I could check. Almost.
AS for it being a technical glitch, if it's real, there's no way it wasn't intentional. You don't model and skin a part like that under a dress and then render panties on top of it - you;d just draw that part of the skin as panties.
If it's true, who ever is responsible for it will almost have to be fired - the publisher can't have things like that in their product and not expect to get lots of troublesome flack. It doens't really bother me one way or the other since it wasn't really made in a malicious way, but it is in poor taste.