I've used MP3Tag many years ago: http://www.mp3tag.de/en/
But it has some problems, eg. it doesn't read m4a tags for some files... Probably you should look for something better.
By the way, for the file you've sent regarding Cover problem, this software shows that ID3v2 tag is corrupted. So I think it's not RB problem - it's a bug in the software you used to edit the tags.