TV makes clicking noises on unsubscribed channels

So recently my wife and I discovered that if we switch to a channel we aren't subscribed to, it causes our TV's audio to "click" rapidly. I believe it comes from my set top box because it stops whenever I unplug the HDMI cable. I have tried a different cable, but the issue persists.

My TV is a Sony X900E, less than 3 months old, and I only subscribed to Fios in the last 6 months as well. Any ideas what causes this clicking, or how to get it to stop?