Have you tried using the id in the folder name so plex will force match it against what you want. So, for this example and I Love Lucy - TheTVDB.com you can use I Love Lucy (1951) {tvdb-70584} which should then match it.
If you want to match against tmdb I Love Lucy (TV Series 1951-1957) — The Movie Database (TMDB) then use I Love Lucy (1951) {tmdb-2730}.
You may also need to plex dance the show depending on previous failures.
