So would anyone say arresting the Sim who keeps appearing usually works? Because there's a blonde gardener who keeps showing up but she's in the gardener uniform so of course she doesn't fit the clothing, and she doesn't have the right traits either (this time the clues are Blonde, Young Adult, Long-Sleeved Blouse, Skirt, Self-Assured, Female) but nowhere on any of the lots is any Sim who does fit those traits, yet I see this gardener chick each time (and not only on lots with gardens).
I ended up taking the advice of others and quitting + redoing the career, and this is the new case, but same problem. Ha ha.