Hi there, @Vegassurfer. 👋
Sorry to hear that you're having trouble sorting from the MusicCast app. I know how frustrating that can be. Something to note, individual manufacturers are responsible for the implementation of the Pandora application on their devices so all features available on the Pandora app directly, may not be available.
I would recommend checking in with Yamaha Support here to see if they have any suggestions about the sorting feature within that app.
Feel free to post any results in case other listeners run into a similar experience. 🎧