Unchecked/Checked songs in my self-created Playlists on iTunes disappear whenever I sync my iPod
Running iTunes 12.2.2.25
64-bit
Windows 10
I've been having this problem with iTunes where one of my playlists, "Movie/TV music" started with many songs, some checked and unchecked. I like to upload only songs that are checked to my iPod, however I still want to see all the songs (checked or unchecked) in the iTunes player and listen to unchecked songs when I want. I have been experiencing an issue where I plug in my iPod to sync it and later upon returning to iTunes all songs that were unchecked no longer display on iTunes. This has also spread to songs that are checked are disappearing. None of the original mp3 files are deleted and if I add those deleted songs to the iTunes player they restore to their checked/unchecked position. Any thoughts on this? I'm wondering if something screwy is going on with the sync process?
iPod (5th generation), iOS 8.3