If you look at http://test.musicbrainz.org/artist/7330c7e3-92a3-41ec-9e9a-54b504eb6e34/works there are three artists listed for both works

If you go to one of the works' pages, e.g. http://test.musicbrainz.org/work/9abb3885-499d-35e7-980a-0c7e7e97fa9f there are no credits listed.

Similarly for recordings - there are a bunch of performers listed on http://musicbrainz.org/track/a716add1-3287-4fe2-bacf-ad38b60f12fd.html who are not shown on http://test.musicbrainz.org/recording/a716add1-3287-4fe2-bacf-ad38b60f12fd/relationships