I use Pandora modes for some of my stations and use Discovery whenever I'm on my classical station. Today when I went to listen to it "Tune Your Station" was missing from my classical station on desktop. It appears on other stations. Pandora modes is also missing from my classical station using the app on my phone, but not other stations.
@Cakes Nice to see you around the community.
Pandora Modes isn't currently offered on all stations (including genre stations like your Classical Radio).
Instead, I recommend creating a station based off of one of your favorite classical composers/tracks as the "Tune Your Station" option should appear there.
Hope this helps clarify!