This CDStub is a Various Artists CDStub: http://musicbrainz.org/cdstub/QyIgWr0gldITp7mUCS7AKrDSWtQ-

When you try to import it from the release editor, it doesn't import track artists.

The root of the issue seems to be that the JS WS doesn't return artists:

http://musicbrainz.org/ws/js/cdstub/QyIgWr0gldITp7mUCS7AKrDSWtQ-

{"tracks":[{"length":"3:55","name":"Only Girl (In the world)"},{"length":"3:19","name":"10 Minutes"},{"length":"3:09","name":"Higher"},{"length":"4:43","name":"Hello"},{"length":"3:08","name":"Tik Tok (feat. Sean Paul)"},{"length":"3:03","name":"Do It On My Own (feat. Craig David)"},{"length":"3:12","name":"Losing Control (feat. Deeci)"},{"length":"6:10","name":"Dance In The Dark"},{"length":"3:21","name":"Seek Bromance"},{"length":"3:29","name":"Club Certified (feat. Akon)"},{"length":"3:18","name":"The Rain"},{"length":"3:33","name":"Why don't we just Fuck"},{"length":"3:30","name":"Downtown"},{"length":"3:34","name":"Dans Ma Party (feat. Willy William)"},{"length":"2:49","name":"I'm in Love"},{"length":"3:05","name":"Tick Tock 2 D Beat (feat. Shugga)"},{"length":"3:58","name":"O'Phone"},{"length":"3:07","name":"Open Your Eyes (feat. Laura Zen)"},{"length":"3:21","name":"Hier Encore"},{"length":"3:05","name":"My feeling for You"},{"length":"3:46","name":"Angels"},{"length":"3:18","name":"Live Your Dreams (feat. Soraya)"}],"toc":"1 22 350522 150 17798 32693 46856 68072 82150 95867 110301 138020 153073 168715 183564 199519 215285 231334 244012 257894 275730 289769 304875 318719 335653"}