For me the problem is related to the nighborhood storys they implemented. I had the same problem with the magic mentors, now her and almost with Rory and Lou as well. Even the night stalker from the curse was put into an empty lot and constantly replaced. My whole list of fhouseholds is full of night stalkers that I keep deleting and no - I didnt break the curse!!
Storys seem to use homeless townies and put them into empty lots and making them unplayed households or even mixing the households, this seems to delete their special/hiddentrait. My Volkovs where all split through random households. I never ever touched Celene or the magic mentors but found them in lots that where empty before. I even turned storys off but this "feature" still trashes every of my gameplays with important NPCs just missing from what they are supposed to do or getting replaced without the things that makes the NPC special.
Storys was the biggest trash they could do if they couldnt even prevent important NPCs to be affected. Making a new save doesnt help because storys, even when turned off, messes with my households and townies. I have no mods acitve that could affect stuff like this.
