When I try and do the final blow to win an arena match, I started getting a disconnected message popup over the animation of me winning in the background.  When I try and log back in, it does it successfully.  This would happen for every arena match I was fighting and then it tells me that my account got banned for invalid fighting.  Clearly, this is a new bug within the game and I see others with the same problem.  it says I can't play now until the 20th so I'm going to lose all the daily/weekly progress.