Hair changing back after changing sim

Whenever I have a Sim and age them up, I like to change their entire look: hair, clothes, etc. But I have an issue when I change my Sims hair in CAS, the old hair will pop back on in their work outfits, when they're in the nude, or when they're in hospital gowns (I know I can change the work outfit with the cheat). And I don't know if that's an overlooked problem or an unknown problem. I know I can't be the only one to find this annoying, but I seem to be the only one mentioning it on here. Any recognition on this would be amazing to know I'm not going crazy over here.