2014-06-18, 12:45 (This post was last modified: 2014-11-12, 11:10 by Rouzax.)
Under 12.3 I never had this issue but with a clean install of 13.1 final all songs with multiple artists are duplicated and separated with a /
See screenshot below.
All my albums are tagged with MusicBrainz Picard with the following settings.