Combat Celebrant's Exert trigger did not go off. When attacking I expected to see a triggered ability pop up asking me if I would like to exert Combat Celebrant for another attack, however nothing happened. My opponent was struggling and only had 2 lands with no other permanents on the board, so there was no effect that would have been stopping me, so I could only surmise that this was a bug. Attached is my game log file.