Leaving app restarts my lesson
This has happened 3 or 4 times now: I leave the app partway through a lesson (dative case 2/3) while I'm writing a comment on a question, and when I reopen it, it's quit the lesson and I have to restart. This happens whenever I'm in the comments section for a question, and then switch to another app. So annoying.
So our devs looked into it and this seems to be a problem on Google's end. See: https://code.google.com/p/android/issues/detail?id=26658
Until they can fix this, we'd suggest just restarting your device and opening the app from your app list and not from the Play Store.
Thanks. To be clear, this happens (in my experience) when I leave the app while writing a comment.
I had the same problem too...I just stopped using the app and use the website.