Roamio: Loud white noise then no beeps

I'm using PCM audio and everyone once and a while I get this loud white noise and no other audio. I think it happens when the program is playing and I hit to key that would generate a beep. Thus forcing it to mix audio. Hitting another key silences the white noise, the program audio returns, beeps are not heard again. If I go into audio settings and toggle between PCM and Dolby audio I get the beeps back until the next time.

Bug?