Very bad
Response from developer
Thank you for writing. We would like to understand what happened, and you are the one person who can tell us. We are finishing an update to how answers are entered, and there is still time to get your case into it. Could you write to us at denys.kotenko@icloud.com and tell us which question it was and exactly what you typed, and where you saw it - on the screen straight after the session, or on the map of your facts? Even from memory, that would point us at the right place. If the app is still on your phone there is more we can work with: open the exercise, tap Progress, then All Data under More, and the list shows every question with the answer that was recorded against it. A screenshot of that tells us in one picture what we would otherwise be guessing at. Thank you for taking the trouble to say it.