Problems downloading video files

Constantly have problems downloading video files from various sites. For example, when I right-click on an mp4 file and select "Save Link As" the only option is to save the file type as "Chrome HTML Document" and this will happen all day long - kind of odd as Tor is based on Firefox. Then if I try again a day or so later it works fine and I can download as the correct file type. I have tried restarting Tor browser, New Identity, New Circuit, Safe Mode & refresh and nothing works. The problem just seems to occur and resolve on its own for no apparent reason.

Please advise. Thanks!

Trac:
Username: Phoenix20