why does iphone sync delete genius playlist when only partially played?

I have an iPhone 6+ (iOS 8.4.1) with regular playlists, smart playlists, and genius playlists. Normally when I partially play a genius playlist and sync the phone to the computer, the playlist stays on the iPhone until I delete it from iTunes in the computer. Not anymore, Now when I partially play the genius playlist on my phone and sync it later to the computer, it deletes the genius playlist from both devices. I recently upgraded the computer to Windows 10. I believe it was after I upgraded that my whole library disappeared in iTunes except for my purchased songs. I had to go and find an old library file and re-load in iTunes. Everything was recovered except for the glitch in the genius playlist deletions when I sync. I'm running ITunes 12.2.2.25 64 bit. Desktop is a Dell 2320 Inspiron One.