An artist credit like https://beta.musicbrainz.org/artist/100c277b-ccd4-4ed9-ad7a-266a881a7bfd/credit/1375661/edit, where the name-as-credited is not in NFC (the ï at the end is stored as i + combining diaeresis), can't be fixed: The server claims that "The data you have submitted does not make any changes to the data already present". The same is true for artist credits with unnecessary directional marks etc.