The iTunes service/app in Japan also has a bad habit of automatically converting western artist names into their Japanese transliterated equivalents (eg. Billy Joel → ビリー・ジョエル) despite me not asking for it. Some tracks in your library would get the metadata converted while some other tracks (probably ones ripped from CDs not found in iTunes Match's database) stay as-is, hence both notations end up in the database, making a mess. Really wish it wouldn't do that.