Movie extras are missing

Just noticed that all the extras from the Alien collection are not showing in Plex. Checked the file folders and they are there, but for some reason Plex is not seeing them. Any idea why?? File structure is as follows as an example:

Alien (1979)
Alien (1979) - Theatrical Cut.mkv
Alien (1979) - Directors Cut.mkv
Deleted Scenes
Cut Scene 1.mkv
Cut Scene 2.mkv
Behind the Scenes
Making of Alien.mkv
Trailers
Trailer.mkv

Which agent is used?
The old agent doesn’t support extras when several versions of a movie are present.

When I go to Agents this is what is set:
Movies - Personal Media - Local Media Assets (Movies) is selected, Personal Media is selected but greyed out

Movies - Plex Movie (Legacy) - Local Media Assets (Movies) is selected , Plex Movie (Legacy) is selected by greyed out

Movies - The Movie Database - Local Media Assets (Movies) is selected, The Movie Database is selected but greyed out, Fanart.tv is selected

Sorry, I should have specified where to look.
Edit your library
go to the “Advanced” tab
The agent selector is the second from the top.