Where does plex get the sort title from for a movie file - mp4

Hi all,

I have a playon subscription that I get some movies and tv shows from occasionally. When I download the file it always has a name like "TheMovieName 1950 720p x264 YIFY.mp4". I change the file name and then from windows check all the boxes for the file under properties/details/remove properties and personal information (I am guessing basically metadata?) but when plex indexes the file, the sort title is still the original file name.
I would like to simply have plex see only the file name and use it. Where is plex getting the original file name from and is it possible to change the file properties in some way so I don't have to keep manually changing the sort title in plex everytime? or is this even possible?

Thanks tons in advance.

PC Nerd.