Oculus.Platform.Achievements.Unlock - looks super easy, but doesn't work?

I have added achievements to my dashboard. They show as published. They are 'client authoritative'. They also show up under my app's details page (View Achievements) as achievements that can be earned.

In my code, I am calling Oculus.Platform.Achievements.Unlock( "WATCH_AND_LEARN" ). This seems like a great, super simple API. But it doesn't do anything.

Do I have to do something else? Something to link the app with the Oculus account that is running it? Some kind of authentication? I am not calling any other 'Oculus.Platform.Achievements' methods.