@crinrict Hello!
1. To my knowledge, cooking alone poses no problem. My guys did use the new waffle maker and pizza oven yesterday, each cooking alone and separately, with no incident.
2. It's funny you ask about what I cook, because I thought the Zombie Cake was posing a particular problem. Now, they can finish cooking it, but while the glitch was still operative, the Zombie Cake in particular seemed more severely problematic, but I don't recall exactly how.
3. Could the following make a difference? ... They are living on the Old Penelope lot in StrangerVille. I demolished the underground house but kept the terrain and features above. Their house consists of two above-ground towers (in theory, for watching for threats, lol) and one enormous floor underground, which is as big as the dimensions of the lot. Because it's an unusual lot and because I pushed its limits a bit, I just wonder if that has anything to do with this? Larger lots do cause lag, as you know.
If you need any other tests, I can try them! I would run them myself, but you know this stuff much better than I do.