Even worse, when I'd click to listen to certain songs, it would play the wrong song/artist, like the metadata was hijacked. All of the sudden it starts overwriting my album art with completely wrong art (example: Weezer showed art for a Radiohead album) on both my iMac AND my iPhone, screwing up metadata by putting random songs in albums where they didn't belong (there was a Cursive album where the first track was listed as a Foo Fighters song). It asked to turn on iCloud Music Library and I accepted. Got home and installed 10.10.4 and iTunes 12.2 on my iMac. Some forum posters are saying other metadata for their songs and albums has been scrambled, too, and multiple copies of songs are appearing in their libraries. Try to play Cream's Sunshine of Your Love, and you might hear Vertigo from U2 instead. The Who's Quadrophenia album art, for example, could be replaced with Billy Holliday's Lady Sings the Blues.
Apple's forums are full of comments from users saying their album art, song names, and album titles get jumbled. ICloud Music Library's problems start showing up after installing iTunes 12.2 on your Mac or Windows PC. Thinking about trying iCloud Music Library? Don't. Instead of giving us a unified music library across all our devices, it's scrambling albums and tracks, and even adds DRM to songs you already own which will lock you out of albums you ripped from CD if you ever drop your Apple Music subscription. ICloud Music Library was introduced with this week's iTunes 12.2 and Apple Music release, and it's turning out to be a big bag of hurt.