Hi Boris,
Here's the sequence:
1. Clear stored password, exit Boxcryptor with back arrow
3. Open app again - PIM is shown but will get into app with no PIN after few seconds
4. Enter password, check "remember" and exit again - log me in with access to files after a few seconds
5. Used "home" to get out, rerun the app, now app is waiting for PIN (expected behavior)
6. Used back arrow - same issue - asking for PIN but getting in without it.
7. Used "Home" to get out, rerun the app, used back arrow at the PIN screen (without entering PIN). Got back into the app and I get to my files again without PIN
Phone - Samsung Galaxy III
Android version 4.1.1