343 industries isn't the same thing as Microsoft studios but they are partners. 343 is comprised of some people from bungie and is like a sister company to bungie. In destiny Activision runs the servers and for halo Microsoft studios is in charge of the servers. Any time there is a problem connecting to the servers it is the servers fault because the servers aren't too compatible with the game, the only thing is you can't change the server you have to update the game. Because the servers have not functioned properly the game can be updated to make that more compatible with the server. And even if it were the games complete fault somehow, it would probably be the complications of what is essentially backwards compatibility.