I receive CBS HD on traditional over-the-air broadcast, so in my case the cable provider has no impact. I also noticed frequent audio drop-outs during the superbowl. This also occurred frequently during regular games throughout the NFL season on CBS, so it is not just a superbowl issue. Similar audio dropouts rarely occurred while watching the NFL on the other networks.
Like I said, since I receive CBS on over-the-air broadcasts, this is more likely to be a CBS issue than a cable provider issue.