I've been having this issue since the braver update released. Something got screwed up during that update because I used to never have this issue until that update dropped. The issue mainly only happened if I were to be in a populated block and in the city but it has also happened on occasional instances outside the city which would seemingly happen whenever a gigantix was around which I would assume to be correlated to the specific instance having a lot of players. I've sent a ticket and a crash log to SEGA already and they have already said they were going to look into it, but a couple weeks later I still seem to be having the issue. I have actually upgraded my RAM from 8 GB to 16 GB recently and it seems to have caused the issue to happen much less often (I can AFK in the city when it's populated for many hours now and still be fine), but still happens. It mostly only happens now when I'm tabbed out of the game for awhile and using chrome to browse things when before my RAM upgrade it could happen merely moments after I would switch to discord for a few seconds. This leads me to believe that this might be due to a memory leaking issue that got introduced since the braver update which is causing the crashes. I hope SEGA eventually fixes this because it's a very annoying bug and caused me to actively avoid the city because of this as it prevents me from socializing with the regulars in my blocks and generally having to forcefully close the game constantly and having to take 3 minutes to log in each time is just not fun to do.
Converse with fellow players