I tested this both by doing a test build and downloading your save.
In my test build in a vanilla game, I could not make it happen. No dirt floor appeared for me. I was able to paint the upper level walls with no problems
However, in your save, also in a vanilla game, it did happen. But at first it didn't. I entered the lot in build mode straight from the map and painted the upper walls with no problems No dirt floor appeared. But after reloading and going into the lot in live mode then going into build, when I tried to paint the upper level walls, the dirt floor appeared and you are right, once it shows, it can't be deleted any way I tried. But I was able to make it go away. After I figured out that I couldn't delete the dirt floor, I used the undo arrow to back completely out of everything I had done and started over. This time though, the dirt floor did not appear when I tried to paint the walls. After that, no matter what I did, the dirt floors did not reappear.
So there is some type of glitch on that lot but it might be fixable. So I suggest you try again and see if using undo will fix it for you like it did for me once the dirt floor appears.
Hope this helps.
@CGrant56 Thank you! And yeah, after posting this I did test on another lot and I wasn't able to reproduce it again, a bit weird but quirks happen. I'll definitely try your method of undo'ing until it complies. ty!
Update: So the undo method isn't working for me. Luckily I have another save now where I've squished it down into one floor (I hope the sims dont get suspicious of the very low sky) but I'd love to see this fixed ☹️ It's really weird how I haven't been able to recreate it on another lot though.
Edit - I did a fresh save and built something similar on the same lot (default house) and it happened whilst changing a full wall to a half wall on the upper level. This lot had the pool on the lower level and half wall AND full wall rooms on the upper. The undo method still isn't working.
I removed all the inner rooms on the upper floor so it's just one massive square. Painting the walls then didn't create the dirt flooring. However as soon as I any room that isn't attached to the outer walls, the bug appears. If a room IS attached to these outer walls, the bug doesn't appear. I have a feeling it has something to do with how the game identifies rooms, especially at basement level?
Update: Okay! Using this same theory that it has something to do with an 'inner' room, I was able to recreate it on hindquarter hideaway!
The bug persisted with and without a pool, and without an inner room on the lower floor, as long as the upper floor has a room that ISN'T attached to the very most outer walls, the game breaks and creates this irremovable floor. Bug officially persists on multiple lots~
(CM: Multiple posts merged. Check out this post for tips on how to edit and add more to a post.)
