I entered an artist-place relationship between a teacher and the school he teaches at, with subjects: "instrument: trumpet, instrument: trombone, instrument: tuba, subject: wind conducting". The instrument split turned each one into its own relationship, which seems sensible, but rather than also splitting the subject as well, it gave back three relationships, "trumpet and wind conducting", "trombone and wind conducting", "tuba and wind conducting". Ideally we'd split this into four (and split every subject too), but at the very least we should try to avoid the duplication.