That’s a Linux (and similar) issue. When Linux updates via it’s package managers it will update Firefox in the background even though it’s open.
This is fundamentally wrong. If you are using Firefox on Linux, you would not update at a time when you’re working - because you KNOW that you have to restart it.
It is considered a ‘User Error’ if they update their system and then complain later that they’re unhappy that they suddenly need to restart something.