I started a new save and got some tenants into my rental buildings. One of my tenants passed away and the rental became vacant. I then evicted another tenant and their rental became vacant too, however, after the eviction, the first rental (of the sim that died) did not stay vacant. Nobody was in the rental itself but the game classed it as vacated. I cannot unjustly evict the tenant, because they don't exist, they don't break any rules either, because they don't exist. Going into Manage Worlds doesn't show the rental unit as a rental at all.
i'm having this same issue and its actually driving me mental
