You are supposed to add the year to the file name and/or the folder name. Which then can assist Plex in matching your file to the correct record on the online databases.
Name your files correctly, organize them into folders as recommended
https://support.plex.tv/articles/categories/your-media/
You might have to perform the Plex Dance with files which were previously ‘mismatched’, to clear the mismatch from the internal Plex database.
If the above, generic tips don’t result in improvement, please tell your actual file names and folder organization.
