User blog comment:Sylvandyr/The math behind the Battle Arena/@comment-74.109.61.129-20130617205126/@comment-4830404-20130617223145

Sounds like rollback caused by fluctuating Internet connection... I had a more annoying bug. My game crashed in the middle of a fight. When I came back, I had neither won nor lost, but since I went in already, the cooldown was started and so I didn't even get a chance to retry the battle that hour :P