Load Error Code 800/801

This was happening mostly with the lot of my played household on my main save, which was also experiencing the default neighboring lot appearance issue and random lot bulldozing issue at the same time. In fact, my played household (in Oasis Springs) experienced the lot bulldozing issue first, with me repeatedly having to rebuild the lot every time I re-entered the save, until it finally culminated in an 800 error when I travelled with one of the household Sims and then tried to return to the home lot (both within the same gameplay session).

I haven't experienced any new 800 errors on that save since getting rid of all R-rental lot types, but the already-corrupted lot is still giving it. (I'm going to try removing it with S4S as per these recommendations.)