In all honesty, their hotfix just solves the issue of people making games and leaving extremely fast. They didn't actually fix anything to do with the quest. I did a quick test and created a game with the host, waited in the game for about 5 minutes. I then joined with my leech, and continued with the process with the host. I left the party on my host once the dialog started and my leech got the reward. I made the game again using the host and repeated. It seems like they simply added this fix as a way to prevent continuous game creation as that was probably bogging down the servers. If you think about it, it makes sense. Why keep a game open when the host left it after 15 seconds? They're simply freeing up resources on the servers.
The big question is did they really put this in place to fix this bug, or did they put it in place to fix the other pressing lag issue?