The only time I've seen that is if I haven't updated in a super long time (e.g. on my Windows partition, which I use like once/year). If I'm using it normally, it installs in the background and I get the new version when I relaunch it. I primarily use macOS (work) and Linux (home), so I guess it's possible my occasional Windows experience is how things normally go, but I think that's a special case for when FF is so out of date that it's unsafe to get without patches.