Why does iTunes not sync accurately or completely with iPhone?
My Classical Music playlist on iPhone is corrupted by songs from other playlists. Settings and smart playlist rules in iTunes on MacBook Pro are correct and govern the contents of smart playlists. Yet these playlists do not accurately sync with iPhone, nor do all of them copy over to iPhone from iTunes on MacBook Pro.
MacBook Pro
macOS High Sierra, v. 10.3.3
iTunes v. 11.2.6
iPhone 6
MacBook Pro with Retina display, macOS High Sierra (10.13.3)