I know there is already a thread for bugs and glitches. This one however needs attention, and I'm worried it will not get seen in that thread.
I have encountered a bug in matchmaking that restricts my field of vision. All I can see is the very tip of the barrel on whatever gun I am using. The only thing I know for sure, is that I did not select a loadout when the game started. It auto selected for me. This bug does not go away after the match is over. It doesn't go away when you switch gametypes. In fact, it doesn't even go away after dashboarding. I looked pretty hard through Google and various forums, and I didn't see any reports of this glitch.
The reason this is a game breaking bug, is because the decreased field of vision makes it extremely difficult to navigate around the map, and judging distance is a nightmare.
Here is a video for proof of the glitch.
http://www.youtube.com/watch?v=qlTHQiRe0_k
Update: I've discovered how to reliably end this bug. I am still unsure of what causes it though. Starting a match in spartan ops, or any game type preceded by a cut scene, will end this bug.