Ive only got partway into the game, but the entire first mission getting rescued i had perfect audio with only minor exceptions once or twice, but once i got into the Liberty Dome it is nonstop problems.
There may be some sound bugs with the game concerning Optical Input?
According to my surround sound box, i keep losing Dolby Digital EX. Thats the light that keeps flashing on and off whenever the audio cuts or stutters.
Edit again: Im now losing audio quite frequently even through the HDMI connection straight from the box to the tv...sounds extremely scratchy.