I'm using MusicBee version 3.4.7749.
I noticed today that music I've added to my library in MusicBee in recent months shows as having 2 album cover images, even though there's only 1. For example: -

If I switch between the 2, nothing happens.
All of my albums are stored and tagged the same way. Each album is in its own folder. Inside that folder is a hidden folder.jpg file, and that's also embedded into the tags of the files. If I open a file in MusicBee's own tag editor, it only shows 1 piece of artwork there.
It's obviously not a major issue, but I just wondered why it's happening. It only affects music I've added to MusicBee's library in the last few months. When I check music I added further back than that, it only shows "Image 1: Album cover" and that's it, even though the files are stored/tagged in the exact same way.
This may not even be a bug, but I'm just wondering why it's showing "Image 1: Album cover" and "Image 2: Album cover" for the albums I've added recently, but not older ones.
Thanks!