I found this. https://superuser.com/questions/1451210/how-can-i-make-firefox-stop-forcing-me-to-restart-my-browser

On Linux, disabling Firefox updates in Firefox itself will not fix this issue, because Firefox’s own updater doesn’t actually have this bug! You get this warning when the Linux package manager has already replaced the files underneath the running program.

You say it’s windows, but I think you said it’s a work machine so maybe they’re updating firefox from under you?