The game froze this time when when my opponent quit as I killed him.
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At first I though the game just froze completely (besides the red sparks), but I decided to wait a few minutes and it then said he had quit. But when I was trying to hit the ok button, it was doing nothing. So I decided I was going to hit the quit button, but it was gone again along with the zoom button ( which I forgot to mention before).
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Another thing I would like to point out. When I decided to watch the replay, It said I had won and not " so and so has quit". Also, the replay bar doesn't go all the way to the end...
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So, I think when someone is receiving a hit and the person quits in the same time, It causes the game to mess up slightly somehow. That is just my guess though.
Also, after noticing the buttons Disappearing, I decided to do one more battle to see if it would happen again. After the battle, I looked up to see if the buttons were still there, and as I guess they were not. I just did not notice it before because the buttons normally hide behind the pop up that usually tells me if I have lost or won.