Hello
My friend and I were playing a few games of skirmish yesterday against only AI when we ran into this issue. Apparently whoever hosts the game seem to crash whenever we reach the condition of an AI defeat. I hosted two games and crashed and had my friend host the next game and he crashed as well. It is only the host that disconnects from the game, the other player was able to stay in the game as well. We both tried lower graphics settings and restarting our games but did not have any effect. When I tried skirmish by myself today, it works perfectly. It may seem to be a host networking issue.