I have this one too with some lots:
This issue started with the For Rent patch. I had 2 computers, 1 on For Rent patch and one on the patch before that, both with the exact same save file. Some of my lots that were already in my world, were consistently crashing / endlessly loading only on the For Rent patch, and were without issues on the pre For Rent patch.
Luckily I tested all my 300+ lots and was able to delete those that now had issues, before updating my main computer to the latest patch, without losing this save file's lot slots forever.
One of the lots it happened to had lots of litte water emitters, partially stacked, and I read it might be the cause, but even removing all emitters and the pool did not fix the lot. Removing all furniture could potentially fix it but there was no point in trying such a lot, as I'm not a builder that can replicate the beauty that was there before. I have other lots with emitters stacked and those are not breaking..
Additionally: Every now and then I have a lot in my worlds that was working perfectly after For Rent patch, and when I load into it from World mode into build mode, after having been on the lot in live mode some days before, it now crashes or endlessly loads. Something seems to be possible in live mode that breaks a lot afterwards. And often these lots then can't be bulldozed as it endlessly loads after you try to leave the lot post bulldozing.
For me it once happend with a retail and once with a gym. Both working correctly last year, and then suddenly after going to the gym / visiting this retail, they couldn't be loaded or loaded out from anymore. In the case of the retail it only broke as soon as I moved 1 piece of item in build mode, any item, then it was endlessly loading on exiting to manage worlds.
I also experience this issue when placing lots from the gallery, most often these are lots that are huge, like churches / castles, but I also had it happen with smaller lots. (This is independent from it randomly happening after placing several lots after another - this issue here is for very specific lots that can be reproduced each time i try to place them).
Hope this experience helps debugging the issue.
