RedIntoxication I've run into that with several apartment lots. It took a while, but I did find a way around it. So, what you need to do is place the apartment as a room on a vacant regular residential lot for editing. Move all objects including wall mounted objects in the perimeter tile adjacent to the other apartments. Just move them elsewhere inside the space. Delete 1 tile of any wall that intersects that same perimeter wall. Save the lot as a room to your library. The objective is to completely clear that 1st tile along any wall shared by 2 apartments. You usually don't need to clear the perimeter tiles along walls that abut the outside or shared corridors/elevator lobby.
Then go to the lot where you want to place the room and attempt to place it. If it does place, then redraw the deleted wall tiles, apply wall paint, and replace the objects you moved before.
If it still won't place, then you might have to clear 2 tiles. All my apartments that wouldn't place were only off by 1 tile and placed with clearing just 1 tile but since you mentioned that yours look like it's off by 2 tiles, you may have to clear 2 tiles adjacent to that perimeter wall.
Hope this helps.