I havent played Call of Duty much but i have had a similar problem with my G6 Lite with other games randomly freezing/garbled audio and they have been fixed by cleaning the contacts on the G6. Sometimes i take the G6 apart (the one screw) and clean the contacts there and put it back together and that has fixed it for me.
Oh and i am pretty sure i loaded the game as i always do. Soft Reset DoFat Force R/W and i likely trimmed it.