While I still haven't reproduced the exact same results in the repro project as I have in the main project, you may still be able to track it down.
One key thing I noticed in the main project while debugging is, during the second play session, the solver and updater from the previous play session (which were marked with DontDestroyOnLoad) were hitting breakpoints, indicating their activity. If you can detect this in the demo project (even though it doesn't always cause problems), you'll probably be very close to the root cause.
DontDestroyOnLoad is definitely a good lead. If you have trouble, I can try doing the opposite approach to reproducing the bug - instead of building up to the situation I think caused the bug in the repro project, I can remove stuff from the main project until it stops. Hopefully I can remove almost everything and still have the exact same symptoms occur.
It might also be a good idea to do something about the same solver being added multiple times to one or more updaters. It REALLY seems to hate this. Burst will puke all over the console, and Oni will outright crash Unity.
One key thing I noticed in the main project while debugging is, during the second play session, the solver and updater from the previous play session (which were marked with DontDestroyOnLoad) were hitting breakpoints, indicating their activity. If you can detect this in the demo project (even though it doesn't always cause problems), you'll probably be very close to the root cause.
DontDestroyOnLoad is definitely a good lead. If you have trouble, I can try doing the opposite approach to reproducing the bug - instead of building up to the situation I think caused the bug in the repro project, I can remove stuff from the main project until it stops. Hopefully I can remove almost everything and still have the exact same symptoms occur.
It might also be a good idea to do something about the same solver being added multiple times to one or more updaters. It REALLY seems to hate this. Burst will puke all over the console, and Oni will outright crash Unity.