Are your files in mp4/m4v containers, perhaps?
Go to
- Settings - Server - Agents - Shows - TheTVDB
In there, grab the line ‘Local Media Assets’ with your mouse and drag it downwards, so it ends up being at the bottom of the stack of active agents.
Repeat the same under
- Settings - Server - Agents - Shows - TheMovieDatabase
- Settings - Server - Agents - Movies - Plex Movie
- Settings - Server - Agents - Movies - TheMovieDatabase
Then perform the Plex Dance with movies which were previously matched wrong by default.