-scene is one of the naming suffixes reserved for local Movie Extras.
https://support.plex.tv/articles/200220677-local-media-assets-movies/
Local Extras won’t appear as a separate poster in your library list.
Instead, they appear as Extras if you look at the preplay page of the movie they belong to.
This requires that the movie and its associated extras are situated in one folder of their own. All files in this folder must be named according to the rules laid out in my linked document.
There must be only one ‘main’ movie file in the folder, not several.
All other video files must be named like ‘Extras’.
