My own Lot got corrupted while building it ?

I have some type of an update on this (if anyone is even reading xD), with the hotfix of today i got some motivation to look into it again, also being able to repair the game again, made me retry. I saw some peoples lots getting corrupted by terrain, so i thought it has to be that, but no i managed to replace the lot in one save, and rebuild the last gallery save of my lot, slowly retracing the build step-by-step, it seems to be getting corrupted by placing stairs on the front of the building. It's a round room, pulled one tile bigger to place a door and as soon as i place those stairs infront of the door it's over. The stairs are from the new ep and nothing crazy, just sideways placed stairs at the front of the lot. But one bad thing though, my save where i originally started building that, seems to be corrupted now, i can't replace or acces the lot in there.