Since the 1.1.3 update, I've experienced a total loss of sound about 5 seconds into the round that last 5-10 seconds in total before my sound comes back. I thought I had identified it having to do with too many people using voice chat at the same time, but I'm not sure.
Edit: This time it happened during the pre-round countdown and lasted about 5 seconds. Public - Firefight. Has happened on multiple maps. I do not have the profanity filter option marked either.