Married sims keep becoming brothers

These are sims I originally made in CAS in the same household as single not related sims. Now whenever I try to change anything in CAS while playing their household they get a Brothers bit. I have tried removing the bit both with MCC and UI Cheats but it always comes back when I reload their house. I have tried entering CAS multiple ways with and without mods installed but if I change anything they get the bothers bit. After getting the brothers bit if I go back in to CAS it still says they are spouses under family dynamic and their romance bar/satisfaction never goes away, but their attraction does.