Checked on the official forums and people arehaving the same issue amongst other mic related issues. They are working on it as we speak. Seems it's a crapshoot at this point and can lose mic audio at any time.
Another time where being a mutli console owner benefits me. My friend and I will just use xbox live headsets to chat until they fix this. --- http://i41.tinypic.com/1609a9h.gif "If you can eat your food while everyone else is losing theirs and blaming you, you straight, homie." -Big Smoke