That’s a Documentary.
TMDB lists it - and that’s where my match for it came from.
Do this and your MP4 files will work the same as your MKV files:
With LMA in the top slot Plex is preferring the embedded title field in an MP4 - which isn’t named even remotely like an extra should be, I would imagine.
External subs and extras can live happily in the same neighborhood (folder):
Note: that second version of the movie doesn’t live in the same folder as the movie version with the extras - and that second version must go in after the first one with the extras. <—at least that’s how I had to do it a couple of years ago - and haven’t had to mess with it since then - until just a few minutes ago when I stripped out a Sub, named it and placed it in the folder with the movie and the extras - to find it works fine… 'cause I didn’t know… until right now…lol
