A Played ghost is haunting other residentials?

I don't think it is necessarily a thought-out feature, but I don't think it's a bug. I believe the game is working for you as designed. For the spooky lot trait I imagine the game searches for ghosts in the households (including played ones it seems) and uses them. I think that is better than generating truly random, new ghosts most of the time but I can see why it could be annoying...