The first bug is: The challenge time for x-10 stages didn’t refresh from last day.
I have looted some stage last day and the challenge time went to zero. I fell asleep while the app running in background and wake up this morning and the challenge time didn’t refresh as it should.
The second bug is: The arena battle didn’t end after i cleared all heroes of enemy. I had to restart the game and the battle was counted as victory.
Screenshot for proof.
UPDATE: I closed the game and cleared it from background and restarted it, and now my challenge times are refreshed as it should.