I've noticed that when I go to an apartment from which a sim has moved - say moved out to a house or joined another sim - that the sim is still hanging around the building but no longer has an apartment. The sim fusses about being hungry, needing the bathroom, and needing sleep. Meanwhile the real sim is residing elsewhere in the neighborhood. The copy that is left in the apartment is sort of a "ghost".
Does anyone know any fixes for this problem or workarounds?