Can't clear relationship credits

If you clear a relationship credit, it'll submit an edit, but won't actually change anything. e.g. https://musicbrainz.org/edit/35681154

But https://musicbrainz.org/artist/c296e10c-110a-4103-9e77-47bfebb7fb2e/relationships still shows:

other databases (as Bob Marley): http://rateyourmusic.com/artist/bob_marley [info]