On the web site there is tab after Grammar called Exercises but it is not showing up in the app. I tried this lesson on the current version of the app (0.9.5) and got the same result as you. Its a bit unclear what CPod means by a “practice tab” since that does not seem to exist. Are they referring to the Expansion or the Exercises? I don’t know. I seem to remember this issue being addressed previously, but there are now multiple threads about the app so I’m not sure where to look. I think the answer is probably that the exercise function has not yet been built into the app.
Update: okay, I found it, in a comment by Gwilym elsewhere in the forum.: “Sadly the exercises have never been a feature of the apps. They prove quite difficult to implement, having been built on quite old code. Currently, we’re working on getting courses/playlists added as well as some simple way to save vocabulary and review flashcards.”
So no, you are not missing anything. The app does not include the exercises.