If you have previously subscribed to iTunes Match and have a large music library stored in the cloud, you may want to be careful when signing up for Apple Music. When I signed up for the free trial, my existing music library in the cloud became totally disorganized. Albums became split up with some songs showing the wrong artist. Luckily, I have backed up my old library and have turned off Music in the Cloud on my iPhone. I am perplexed as to how Apple could have made such a mess of iTunes match by mixing up the metadata associated with the albums and artists.
I am now searching for a fix. I cannot find the option to update iTunes match after upgrading to iTunes 12.2.
I have noted that many people are experiencing this problem according to the Apple Support comments I have read.
I love Apple Music but I would not have signed up had I known my music library in the cloud would become so messed up.