I’m very curious to see who all is experiencing this. Happens to me very frenquently in team dubs I would say at least once out of every three games. Game starts my teams goes up by a large amount losing team quits instead of getting the win we get credited with the loss and de rank. Even had it happen before the game actually starts. Team backs out in the voting lobby and i de rank. Needs to be fixed ASAP makes it impossible to rank up in team doubles.
I believe this happens because when Halo 3 was released, people would boost team doubles. They did it by joining a game with their friends, getting a couple kills and having the losing team disconnect, by unplugging their internet. The winning team would rank up, and the losing team would have no repercussions, because they lost connection to Xbox Live. My guess with your problem is 343 caught on and sometimes takes away a rank if the same thing occurs. I have had the same experience but with the Halo 4 playlist. My team will win by over 30 kills, and I will still go down in rank. It’s very annoying, I hope it’s fixed soon.
I have played Halo 3 but it was a year before I got Xbox Live and when I did get Xbox Live it just stopped working and I have no idea why. But this dose sound like a issue that needs to be fixed I really don’t care how old the game is but a lot of people still play that game and it sounds like a problem that can easily be fixed by a simple patch.