When 343 Industries released "Halo: The Master Chief Collection" back in early November 2014, the widely anticipated port of early Halo games to the Xbox One started out not with a bang, but a whimper. Users were beset with problems, so much so that 343 Industries released an apology and updated their servers to try and fix the problem, and then later offered a free month of Xbox Live and more, and more apologies, to Halo: MCC users.
The problems, however, continue, and yesterday, based on information found in a leaked Xbox One SDK, Reddit user "jcs879" started a thread positing a somewhat different theory of what may be causing the issues other than "it's all 343 Industries' fault".
Microsoft changed the way that chatting worked from the Xbox 360, where users could chat even if they were playing different games, to a "matchmaker" system where, at first, users could only chat with players in the same game. The system has had a number of updates to improve usability, but doesn't appear to be working properly, even now. The Reddit original poster described the problem:
The 2015 Multiplayer system has been in preview form for a period of time and I believe Halo: MCC was the very first game to try it out and it failed miserably. The issue is on the MS backend. They thought it was working fine but all the handshakes don't work. This is why 343 has been unable to fix the problem. They didn't really create the issue, they used the system they were given and they don't want to go back now because in the end it will be better.
I also believe this is why 343 included a p2p backup plan, if the new matchmaking failed to connect to dedicated then you would revert to p2p.
The thread has garnered over a hundred comments so far, some pointing out that 343 Industries isn't totally off the hook:
have you checked out the bug thread? Please tell me you haven't.... you'd know immediately that 343 is accountable for quite a few bugs. If what the OP said is accurate, that just relieves 343 of the most prominent issue with MCC. They still have a huge list of other issues.
Another commenter points out that no one really knows why 343 Industries went with the new system:
Just going to point out the idea that MS forced 343 to use this new party method is total speculation. Not that it's impossible, but there is no evidence at all.
Obviously between Microsoft and 343 Industries, a number of issues with how the Xbox One handles chatting and matchmaking still need to be resolved, and both parties have a lot of work to do. Still, it's interesting what comes out of careful reading of documentation (especially leaked documentation!).