Since you are not telling us neither OS, nor what happens with the files during scanning, I assume they simply doesn’t show up in your Plex library?
If so, I suggest checking file rights and/or ownership
(Hint: compare to working files)
And if not above, then:
- Provide more info
- Make sure PMS logging is set to debug
- Do the Plex Dance on the entire show
- Upload a zip with PMS logs
