Deleted walls wont disappear :/

I'm making a loft style A frame home and added a 3x2 bump out to the second level, outside the main room making up the second level. When trying to open this bump out, so I can add the stairs, I'm unable to delete the wall that connects the two rooms. I'm able to delete the floor inside the bump out, however, when I try to delete the three walls, it doesn't go away. But on my screen the walls will still be there and I'm unable to place the stairs there. As it's still there, though and i try to delete the wall again, it says there's nothing to delete. I've tried to replace the bump out to try again, it just does the same. I've also tried to restart the game, tried spandrels, and changed the foundation. Nothing seems to work. I have the terrain and shape built and I'd be so sad having to rebuild it. BTW, I'm building in the new cottage living world on the lot Cordelia's Secret Cottage.