[Open] - Passive Sims disappeared from house and no longer exist/are related

This has just happened to me! I had a passive sim who started as an NPC my sim married and I had made her playable for quiet some time. She was in the middle of career/hobby stories. I’d made her passive for a while and when I came back to her house she was gone from the portrait and none of my other sims have any relationship with her!! I’m so discouraged to see this happens regularly 😢😢. It’s very sad to lose a sim after putting so much time into them!