I'm on a Google Pixel XL (Android N), but in the past couple weeks the "swipe down to view sentence translation" functionality stopped working. Same thing happened on a Google Nexus tablet I own. Used to work great, but no longer.
Also, FWIW, I actually preferred the web app (I had installed it to my home screen on Android - felt indistinguishable from a Play Store app like that) over the native app, mainly because the web showed the number of characters "hangman style" in the answer. The web version really worked fantastically on my phone up until this bug - I'd question if a native implementation is worth it.