In the savegame referenced below, you’ll notice that the small pre-fab multi-sleeping quarters is having some issues. Because of the current limitation of not being able to delete or modify building instructions once issued, coupled with the fact that you are able to stack multiple pending instructions on the same blocks (example: “Place this fancy door here. No wait, I meant this less fancy door. No, just kidding, I really meant the fancy door.”), you’re often left with a never-finished building that Hearthlings simply ignore entirely.
Similarly, when placing beds in the upstairs floor of the multi-function building nearby, I was able to get Hearthlings to literally stack two beds on top of each other within the same space. I was even able to instruct them to later move one copy of the bed to another location. The UI displayed both beds layered on top of one another when both were placed.
Referencing Savegame from AI Pathing Issues with Multi-Floor, Multi-Use Buildings: