Lots not functioning properly/disappearing between manage worlds and edit lot

I've had this issue for the past couple of days, sought help from other sources and repaired the game multiple times, but I haven't been able to fix this. Basically, I have been attempting to place a residential lot in San Myshuno, on the Old Salt House lot. I placed a lot from the gallery, made some edits, then saved and closed my game. When I opened the game again, I could see the lot I placed on manage worlds. When I load into the lot, it's completely bare, as if it has been bulldozed. I experimented by placing a different gallery lot on the lot next to that one -- the karaoke bar. This also showed properly on manage worlds, but when I load into that lot, the one next to it shows my original, edited lot I had worked on! So I went back to that lot, and it was still a blank lot, but the karaoke bar had reverted to the default. I am very confused and don't know how I can fix this. I started a new save file as a test, but in that save file San Myshuno won't even open, it just shows a blank white screen. I would appreciate any tips, information about if this is a game bug, a problem with my saves, anything to fix it. The first image is of the view when I load into the karaoke lot, the second is when I load into Old Salt House.