Why is the browser updating every time it starts?

This is not a gripe about frequent updates, nor a case of being redirected to the "browser updated" page every time I start Firefox. What is happening is that every time I open Firefox, I get a message from Windows asking for permission to let Firefox perform an update, then after I click "Yes" a window with a loading bar that says "Firefox is installing your updates, this may take a few moments..." or something similar to that comes up, and then the browser opens when it is done updating. This happens literally every time I start Firefox, even if I close it and immediately start it again. This has been happening for several days now, and refreshing Firefox has not helped. Help?