Suspicious Firefox Download

My Firefox browser indicates that it is currently up to date with the latest version.  Yet I keep getting a pop-up window that has the Firefox logo and says a critical update is needed.  The file it asks me to download is "ohphafemaleagent.org" but when you download the file, the name shows up as Firefox Update.  I scanned it with my Norton security, and Norton indicated no threats.  However, it just doesn't seem legit to me.

Has anyone else seen this?