I tested this in my save and I no longer see this issue.
I will mark it as fixed.
i have four children in my household. One of my children maxed out his mental skill legit, but later suddenly got from 1 or 2 in creativity and motor all the to max. Two other of my children have suddenly maxed skills as well. One hasn't, but she probably will end up doing so soon. I don't know what each of them were doing, but it sounds like it's possible that they were playing Keyboard Commander. I don't know for sure, but..yeah. It's a bit annoying when I was trying to get them to have a single specialty and I max out their child skill all on my own, as well as finish the appropriate aspiration, but I guess I'll take four ultimate children if this bug doesn't stop.
