I can tell you exactly what it is, because it happened to me before when I changed from one version of the insiminator to another one.
The objects like the red heart which is the relations adjuster was sticking out of one of my sims butts.
and when I used the move_ objects cheat it said "plumb bob" when I picked it up.
and the funniest one was this sim man had the career adjuster stuck around his waist, even when he went to the bathroom. I had to use the move_objects to get rid of that too. I wish that I still had the pictures, they were hilarious.
one more thing, don't worry because after you delete the hearts the regular plumb bob will come back.