Unmatched episodes from specific season, why?

Plex Media Server Metadata & Adding Files
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Please try this naming:

Top Mecanic 5 jours pour restaurer une épave/
  Season 6/
    Top Mecanic 5 jours pour restaurer une épave - S06E16 - TBA - [WEBDL-720p][FR].mkv
    Top Mecanic 5 jours pour restaurer une épave - S06E17 - TBA - [WEBDL-720p][FR].mkv
    etc...

I removed the [imdbid-]
I use the complete title in folder name and file name.
I used Season 6
I removed an extra - in the file name.

Name all files and seasons that way, then Plex dance the whole series is my suggestion.