Sorry that I didn't think of this possibility at the time, but probably you're using a BS.Playlist under Media Library. The data which are stored inside the mp3-files don't show when using a BS.Playlist. They only show using BS.Media-Audio for files which you've added to BS.Player's library first. (The BS.Playlist can (i.a.) be used
as a source to add titles to the library.) Similar to the Album-art issue from this thread:
Bs player mp3 album Art Cover ??