It is pointless to try and find why Plex is doing this or that with non-conforming file names. Stick to the naming conventions and you can reduce missing files and mismatches by almost 100%.
And I recommend you to rename your files before adding them into Plex. Because Plex is storing a ‘bogohash’ of your media in its database. If it mis-matched an item because of a non-conforming file name, the bogohash is stuck in the database and Plex will continue to recognize this file as the wrong media – even after you rename it afterwards.
This state can be only cleared with the Plex Dance. Which is bothersome and pretty annoying to do.
Hence my recommendation: rename your files by default.
The Plex naming schema is the most non-ambiguous of them all and is well understood by other media managers/player/servers.
So there is no reason to not adhere to it.
