If you got an email from the Inspection Team regarding duplicate cover art, this is due to your artwork being used on another release. Each release requires its own unique artwork.
There are no exceptions to this guideline.
If you plan to use similar artwork for a single and full album release, you should make each cover unique by adding the single title on the artwork for the single release and then add the full album name on the artwork for your album release. The different text has to be dominant in the artwork to identify that the artwork is indeed different per release.
If the release is a remastered version, then you can add "Remastered" text to the album cover. That will make it different enough from the previous release.