I had this exact scenario (asking me to restart after an update) happen to me yesterday on pop os which is Ubuntu based. And I've definitely seen it other times too. Having said that, it was absolutely no big deal whatsoever.

I don't remember seeing the other issue you mention. I've literally had some tabs open several months. Have you tried looking for the "restore tabs" option in the History menu when this happens? Afaik that's available even if you don't have any option set to save your tabs