I have been having problems since launch getting into a matchmaking game while I am in a party with someone on the same network. Rarely it will work, but the majority of the time it will not. When it is able to find a game, it usually takes 6 or 7 minutes to do so. We usually set a 15 minute time limit before we give up.
My roommate and I have tried everything. It affects every playlist. Adding a guest or someone that is on a different network does not help at all. I kind of expected this to happen at launch, but it’s ridiculous that it is still happening. Even more frustrating is the fact that I have not heard anything back from 343.