I try to explain it as good as possible.

There is the album "Stab Wounds" from Dark Fortress but as you can see in the screenshot below, the data is totally confusing. The tags are right (as you can see in mp3tag) but Amarok says the band is "Drudkh" and the Album is "The Secrets of the Black Arts" which is neither an album from "Dark Fortress" nor from "Drudkh", it is from "Dark Funeral". So every band begins with D...

So the Databse mixes Title, Artist and Album from 3 different Bands together...


http://hal9k.eu/images/amarokrc15.png

What version of id3 does mp3tag use?
Check with an app that shows you both version 1 and version 2 tags, and make sure they both contain the same information.

It's a FLAC album.