Here's one I have never seen before in KGBvKCround4 (id 1562).
I just attacked the Dragon city on the Bullrun map. It had 25+ defenders in it including an enemy dragon. My stack was a Dragon/Siege+6 Spiders. The combat crashed the game. As in I waited a few seconds then got an out-of-sync error.
After refreshing the browser I got the victory screen. So I occupied the city. The browser hung again. I refreshed once more and this time I see a very strange result. The city is my color (orange) on the mini-map. I can set/change production. But on the game map, my dragon is in the upper left corner. In the other 3 corners are enemy units. If I try to move more units into the city, I enter battle. That battle hangs and I have to refresh the browser at which time my units appear in the city.
Those enemy units are in fact real. When I replay the battle report, the battle crashed at the point my dragon entered against the final 3 enemy units. So the battle never actually completed. Yet it gave me the victory.
Take your time reviewing what happened as I have 5 days to finish my move.
KGB