I am having this bug as well. Recently updated, repaired, etc. New game, new family, the house is Rio Verde in Oasis Springs, the issue is the first floor bathroom. I did push the bathroom in to make it less of a space hog, no MOO used. They randomly just get stuck in THAT bathroom. I don't have to sell / repurchase the door, but I do have to go into Build / Buy mode and either just move the door away from the wall for a moment, or "flip" the door front to back and that fixes it. For about a sim day or so.
There is a child's drawing / activity table near said door, but it and the door were placed by snapping; no MOO, no using the Alt key for finer positioning. There are also some bathrobes on the bathroom wall directly opposite of the activity table, but, again, no MOO though I did use the Alt key technique on the robes. The door in question is the "Simple Single-Panel Door" from the base game.
I have had "visiting" ghosts possess some of the items in the bathroom, and the toilet was pranked by a visitor. If I remember correctly, the toilet getting pranked was right about when the door stopped working properly. Hmm, I wonder if replacing the toilet would fix the root cause....