Adult Sim Missing Bottom Half

I have an ingame born sim with the same issue. They are half mermaid half spellcaster, but in CAS she doesn't have a mermaid form. When in CAS, she has a full bottom half of her body and I was able to plan outfits. As soon as I leave CAS, the outfits are all random again and the bottom half of her body is wonky. At first it was the mermaid tail even out of water (again, she has no mermaid form in CAS), so I went back in and tried to give her all outfits with separate top and bottom items, hoping that my choices would save even if only the tops showed, I'll deal with a mermaid on land it's actually kind of funny, but when I exited CAS not only had my tops not saved but now the entire bottom half of her body was invisible, disappeared, gone. I would have rather had the fishtail than this.