My Sim Won't Age Up

I have a few sims that this is a problem with and they're all twins. They're stuck being a toddler and they're all the older half of their set of twins. These set of twins have been girl-girl twins too. The younger twin always ages up into a child.

So far this has happened with three sims.

With the first twin, I tried to go into CAS and change her age to young adult but the game wouldn't finish loading CAS (in another of my saves, this did also happen with a stuck-in-the-wall unicorn). Later I tried aging her up with the cheat. That didn't work so I tried aging her up with multiple birthday cakes but they didn't work either.

With the second twin, I had aged up her twin sister first but figured out that it had nothing to do with her "immortality". In Edit Town, the twin can't be moved back into the household and neither can anybody else in the same household as her. She also won't appear in the household portrait.

With the third twin, it was the same thing as the second twin except I let this twin's twin sister age up naturally.

I do have mods and custom content in my game. Since this happened, I deleted a mod which I installed incorrectly which was a "No Full Moon Lighting" mod.

With all of these sims, none of them had CC on them.

I've also had boy-boy twins age up and boy-girl-boy triplets too. I'm still waiting to see if the boy-girl twins will grow up into a child in another save of mine.

Any possible way to fix this?