How do I prevent false iTunes ratings? I listen to a lot of smart playlists based on ratings, and I use the grouping field for tags.  For example: Grouping Contains "Mellow", Rating is greater than **.  That playlist has thousands of songs.

Since upgrading to iTunes 12.2, I'm seeing some ratings with black stars, and others with gray stars.  Apparently, the gray star ratings are automatically generated by iTunes.  I've never seen this before.  To make matters worse, songs with zero ratings are showing up in my smart playlists because iTunes assigned them a gray rating.

How do I get rid of the automatically generated gray ratings?  How do I prevent iTunes from ever automatically generating false ratings again?

I've got over 30,000 songs.  I don't want iTunes destroying my ratings system with false ratings!  Just because I like one song on an album doesn't mean the whole album is great.

Additional info: I'm not using iTunes Match (my library exceeds the 25,000 songs limit).  I did check "iCloud Music Library" yesterday while signing up for Apple Music, but I've also tried turning that off and it doesn't get rid of the gray/guess/false ratings.
This is a bug introduced in iTunes 12.2 at the end of June.  It appears that iTunes has done some sort of averaging of track ratings and written them as album ratings overwriting the original per-track ratings.

I've seen this issue with my library of approximately 100,000 tracks and have filed a bug report with Apple in Radar. Removing the album rating data is difficult as iTunes won't reliably show this data in smart playlists and many of the utilities that try to do mass change operations fail when setting this attribute.

The tool I've been using to slowly clean it up is Doug Adam's "Album Rating Reset."  This only works on one album at a time, but if you really care about your ratings, you're going to want to clean this up very carefully to avoid damaging any of your remaining per-track ratings.

I should add that I was also able to restore a number of the lost per-track items by restoring a pre-iTunes 12.2 library to a separate user account , confirmed that the ratings will still present and then used the commercial SuperSync utility to transfer the ratings from the old library to my latest 12.2.2 library using the metadata transfer tool.

What a hassel!  I hope sharing some of my tools helps you with your carefully crafted library.