http://musicbrainz.org/edit/35304410 somehow got added with a disambiguation comment of " ", and is now stuck.
Perhaps this applies to other "Edit" edit types, too.
Error while processing edit #35304410: Failed query:
'UPDATE artist SET comment = ?, name = ?, sort_name = ?, gender = ?, type = ? WHERE id = ?'
( Евгений (bender) Ряд Evgeniy (bender) Ryad 1 1 900742)
23514 DBD::Pg::st execute failed: ERROR: new row for relation "artist" violates check constraint "artist_comment_check" at /home/musicbrainz/musicbrainz-server/admin/../lib/MusicBrainz/Server/Connector.pm line 42.