Is this a reoccurring issue or does this happened sporadically? Do you have any other browsers open while you are viewing the games that could be interfering?
Are you connecting to the internet through WiFi or through a wired connection? I would suggest hooking up the device you are using to view the games to a wired connection to see if that makes a difference.
I have tested it again today using Google Chrome and did not have any issues with audio or video.