Edit the tv shows library and verify that you only add
/mnt/plex/Completed TV Series/IJKLM/
as the source folder.
Don’t go a single folder level higher, nor lower.
I assume you also have other “index letter” folders, beside IJKLM
.
You need to add each of these individually to the library.
All shows except “Monk” appear to be missing a “season” folder level. It is recommended to always add it – even if the show currently has only one season.
The release (year) appears to be missing from all the show folder titles.
https://support.plex.tv/articles/naming-and-organizing-your-tv-show-files/
There is software to quickly fix these issues. My default is Filebot