The short story is that Xbox Live and the OS, especially in functions that involve XBL, are a complete fucking mess. One source says we arent talking weeks until it works correctly but months. Things like parties dropping people when moving from one thing to another. Connectivity issues. Missed invites. Friend requests not working, etc.
Let me get into some technical detail regarding it on 360, the OS handles all of the party and chat functionality. All you do is hook up the XBL VOiP OS API into your game, and it does most of the work for you. With it results in is a shared experience across multiple entertainment. If youre watching movies or playing games, you can do it together. However, this system is entirely different on Xbox One. So, lets say me, you, and Thuway have xbox ones that are online. We are signed in our profiles. Sitting at the home screen, we are considered to be in a Xbox Party on the server. There are no more party leaders. With that said if any one of us decide to start a game, the party is shifted over to that games party system. Each game now has their custom written VOIP. (Pete note: shoutout to thuway!)
I asked if could be fixed soon. He said that anything is possible and Microsoft is obviously working on it but he thinks it will be months, not weeks. Getting online launch games certified is taking so long that its pushing games after launch back.