I thought they've already fixed this already... This happens everytime the host get disconnected because of high ping and the game then freezes. Few seconds later the game will either automatically create you a room to finish the game or get black screen. By then you can't do anything but exit the game by pressing alt+f4.
This happened to me last time.. Well that was like 3 months ago when the game first open the close beta and really buggy. I ended up selling all my loot and earning 200,000 in-game currency which I spend messing around with the armory.. I wish I could have saved those now that I'm back playing again; I could have purchase those new blueprints. :/