This happened a few times last night, I’m in a fireteam with two other people, a game is found, then one or two of us are sent to the home menu (Xbox home menu), and the game resets. But the third person is still in the game and two replacements were found in matchmaking for our spots. As if we were never in the party to begin with.
Curious if this is related to my network (two of us play on the same router, but open NAT and all the proper configuration to allow us to do so), or a bug.