My wife and I are playing unable to party up in the CBT. We had a friend try to invite us both, but as soon as one of us joins a party, the invite drops off for the other. If I try to invite her, I just get an error that says "You can't invite that player to your party at this time."
I hope this issue gets fixed soon. Specially considering it's not an issue (at least for us) on live servers.
EDIT: Turns out my wife had me muted on Xbox after all. Be sure to check if you're having the same problem lol