Why can't the devs have it update in the background or on next startup? I was in the middle of my work when I got this. Now I need to close everything and go through all the logins and 2FA again. 😡
Chrome is much better at this, hands down. It has never interrupted me the way Firefox does during updates.
Are you sure you don't have some other software updating Firefox in the background?
Normally this only happens on Linux when your package manager updates Firefox while it's running, and on Windows that doesn't happen because Firefox updates itself only when you (re)start it.
Not on the Linux systems I'm familiar with. The only way to trigger anything similar is to execute a package update while running FF, at which point new tabs will show a message to restart, but you can keep on using the open ones indefinitely.