I think maybe you are focusing too much on the folder.jpg/cover.jpg, the principle location for the artwork is in the files themselves, this is much more portable because then if youmove the music files you do not lose the artwork.
If I look at Report 701 and Browse By Album I can see there is no artwork for Along Came John (by the way in the screenshot you cant see artwork for Movin’ Along either but this is just because when the support files are uploaded to me they don’t include the images) because it is showing the folder icon. This means there is no cover art artwork in the files themselves
Actually when I look at a track, I can see there is some existing artwork (not added by SongKong) but it of type Other, it should be of type Cover (front) so it is ignored.
Whereas if you Browse by Folder it picks up the folder image
But then I also noted you didn’t actually have SongKong configured to add artwork, did you realize this ?
Then in Report 702, the artwork is now there in the file of the right type, but I guess you did this externally from SongKong because SongKong is still configured not to add artwork