Sometimes I see a different set of hoppers, and my SR gets set back to 0. Why does that happen?
What you are seeing are “fallback hoppers”. When you enter this mode, you will see a UI notification. It shows up on the “Find Game” screen for War Games. In previous Halo titles, you’re dependent on the servers to get the information you needed for Matchmaing, and if they go down, you can’t play. Fallback hoppers are a new functionality for Halo 4, and they allow people to continue playing Halo 4 when there are server issues.
In order to preserve the integrity of the online experience, there are some limitations to this functionality:
• Reduced XP earn rate, counted as offline XP
• Players in the fallback hopper cannot play with those that are using the regular server hoppers
• Player customization is disabled (no armor, loadouts, emblem)
Since the server isn’t actually available in fallback hopper mode, you’ll be missing functionality that the server provides. This includes:
• Spartan Ops
• File Share
• Service Record
• Commendations
• Challenges
• Double XP tokens
You will automatically be switched to fallback hoppers if you fail to download a necessary file. You’ll remain in fallback hoppers for up to 10 minutes after the services return. When in this mode, it’s a good idea to relaunch the game on a regular basis, so you can reenter the regular hoppers as soon as they’re available.
http://blogs.halowaypoint.com/post/2012/11/12/Halo-4-Weekly-Challenges-111212.aspx