Skin Tones Glitch?

Hello friends! 

Has it been an ongoing glitch where skin tones don’t work with genetics at all? I’ve had an influx of black sims, which I found odd because I keep my world pretty diverse. Well, I went to edit a household of my current sims best friend to make her outfits less crazy, and I found that both of her parents are white? They’re Faye and Cletus Herris. All of the kids they had since starting the game have ended up with super dark skin. And now that I’m diving in more to other households, I’m finding that the kids skin tones don’t match up with their parents at all! Almost every sim born since I’ve started the save has been black specifically no matter who the parents are. I’m just wondering if it could be an issue with my game itself where maybe some CC is messing with how the game uses genetics, or if it’s a glitch others have noticed too? I’m all for diversity, but I want the genetics to actually work LOL.