[zenith]

If you could be more specific about what you were doing, it would easier to figure out what happened.

Looking at them, looks like you haven't lost to him in a long time. Did it happen in the middle of combat, or did you win and not click on an option at the end of combat? Or did you happen to hit refresh or another link or have another browser window open or or or...

There are a lot of things that could have happened.