This issue now seems to be fixed in the 1.68.154.1220 November 2020 patch.
Thanks all for confirming it now seems to be fixed. If you start experiencing issues again please post 🙂
It was happening consistently in any lot I opened, especially if I tried to build there. It was far worse on lots I had edited myself, especially when I tried to use the new feature of windows overlapping on tiles, but I had this happen throughout Willow Creek and Oasis Springs.
I say "was happening consistently" because as I was going through to test more lots, specifically San Myshuno since the 2016 Macbook thread indicated it might be a particular problem, I only had this happen once: on my edited version of the Goth family house in build mode. The only thing that was different between these loads/plays and previous ones is that I had turned off my f.lux filter (a third-party app which reduces the amount of blue light produced by my computer screen at night). Even during daytime, this filter is technically active unless you either disable it or quit f.lux. With the filter off, I was able to go into any lot I wanted in build mode, bog it down with as many items and swatches as I could think of, and wheel the camera around in all directions. The only time I had it lock up was when I tabbed out of the fullscreen game to check something else while I was working on the Goth house. I've had problems with tabbing out and back into the fullscreen game plenty in the past, so I don't think it's directly related to the issue at hand.
I don't think there's a fundamental problem with the f.lux app—when I closed the game, turned the filter back on, and reopened the game, I was able to be just as aggressive, even on lots that had frozen on me in under 2 minutes before—but it seems plausible that it was causing some issues since all but a few were strictly graphics-related. Might also explain why resetting the PRAM/NVRAM didn't work for me. Curious to know if anyone else experiencing problems is using this or even the built-in nighttime filters in macOS.
I haven't yet tested all the lots, just the ones that were giving me trouble + a couple of City Living default apartments, and I've done about half an hour of glitchless play in live mode at this point, which is more than I'd gotten before.
