Does it only happen on recorded shows but not live shows?
What model DVR do you have?
Does it happen just on DVR or when watching from a remote STB?
How is box connected to TV?
Is that the only type of connection you can make to your TV?
If not, maybe try another type of connection (Composite or S-VIDEO if you have SD TV )
Sorry so late, didn't see this. I now have a Motorola Box which does the exact same thing but only on HDMI and not component. Just talked to Tech Support via Verizon phone and we switched out the boxes but none of the remotes will turn up the volume on the supposedly bad box so they are sending me out another one Monday and I will send them back the bad box.