@GooglePlayMusic have you removed the feature whereby search shows the results which are in your library? I've playlists I can see have songs from an artist searched for and yet when I search there's no section for the songs in my library 
Appreciate the details – if you're on mobile, check if you have the app's latest version or clear its cache (tap ☰ > Settings > Clear cache). If you're on a computer, clear your browser's cache/cookies. To take a closer look, reach our support team here: http://yt.be/help/i16t