When you (or someone) ripped that from disk - they didn’t remove the embedded tag - so the embedded tag -the bogus one - is making your life miserable.
Make Plex stop reading and reacting badly to the embedded tag.
( you can, however use MKVs for future files - and you can remove that tag in the ripping process as well - for complete OCD satisfaction - I can show you how, if you’re doing the ripping)
