I have tried loading the tracks into foobar2000 and if I look at properties it actually contain a DISCID tag with the correct number set. I don't know if taglib-sharp doesn't read flac-tags properly.
But don't waste any more of your time on this if its only me seeing this problem, I can live with it, and I'm very greatful for all your work.
But don't waste any more of your time on this if its only me seeing this problem, I can live with it, and I'm very greatful for all your work.