Anyone else seeing this? Starting with Sierra and continuing in yesterday's iTunes update, if I add a song to iTunes for an artist that already exists in my library and then add the artist's name, a duplicate artist entry is created instead of the song showing up in the existing artist entry. E.g., let's say I already have 10 Madonna songs and then import another song, and then add Madonna as the artist and/or album artist. Instead of that song appearing in the existing Madonna section, a second Madonna entry appears in the Artists list, even if the song not only matches an existing artist but even if it's from an existing album by that artist. I've tried quitting and relaunching iTunes, and the duplicates persist, so it's not an anomaly that gets cleaned up upon a relaunch.