Roof deleting/overlapping interior wall (wallpaper problem)

Alrighty, I'm going to try to explain the situation as best I can.

I am building a house with a second floor bedroom that is raised up on the inside with a platform. This is because I wanted to add a little porch, which required a raised platform because of the roofline. In order to avoid needing to use stairs or having a floating door, I just raised the room inside too. When I did this, the roofing clipped all the walls and I could no longer see the room. That's fine, roofs are weird in the Sims, and I've encountered this glitch before, even without platforms. So I separated the pieces of the roof to sort of puzzle piece it together. This was working fine until I put the roof along the back wall. Instead of placing and keeping the wallpaper on the inside, the roof wall came inside, either deleting or overlapping the interior wall. This creates a problem with my wallpaper. I've included screenshots below.

Here is where it's fine. The roof is one square beyond where I need it, but there is no glitching.

Then, when I move the wall down so that it is in the right place, the wallpaper on the roof glitches into the interior.

I tested some stuff to see what things might change. Lowering the floor to the proper height (no platform) does not change the outcome. The wall still has that effect. But, if I decrease the slope of the roof by like 2 makes the glitch stop on the side, but not on the whole of the back wall.

I didn't think to take a screenshot of the back wall still glitching even when lowered 2, but I can add that if you don't understand.

I troubleshooted a lot and am usually pretty ok at figuring out weird glitches but this one has me stumped. Anyone else have this issue? Anyone have any ideas on how to fix this? Thanks!