Issues with NPC sims owning two lots

I'm trying to put my sims into appropriate houses because I had the "move into empty lots" selection on and a bunch of single sims moved into super big houses. So, I'm trying to move large families into those homes and now as I'm moving them around sims they're essentially in both houses. I'm trying to figure out if I'm duping sims or if it's safe to just evict and let it go. They don't seem to be appearing doubly in the Manage Households area. So, I'm not sure if it's a weird glitch etc. Thoughts?