Way late replying to this, but anyway.
I've had this same glitch a couple of times, in my WYDC and Epic challenges. Eventually removed a couple of outfits incorrectly categorised as teen maternity (when they should have been YA). Neither of the kids who had the issues was wearing these clothes, but once the CC was removed, I've not had the glitch again, so I assumed that's what it was. Weird "fix", I know.
This glitch is what caused me to save every sim to the bin during their age up makeovers...yes, every age stage. That way I can skip the first half of your solution if it happens again