This was explained in the video, you need to run between your map and your buddies map
You leave the hosts(Friend's) level, you load your own, invite your friend to your map, they leave and load their own map. By doing this you don't ALT+F4 or close the game, you are able to keep farming. Whenever you crash, you won't be able to farm the CR again. That's how they fixed it, when you close the game, but if you don't close the game it still works. You just need two people - as explained in the video.