Thanks for letting us know what you're experiencing. Do you see this issue if you connect your Roku devices directly to the TV? Does connecting the Roku directly to the TV, then connecting the DVR to the receiver via HDMI ARC for audio still result in the same issue?
Please feel free to send me a private message with your Roku account email address, the serial number of your device from Settings>System>About, the specific make and model of both your TV and your A/V receiver, along with any additional details about the behavior, when it occurs, and if changing any Settings in Settings>Display type helps resolve the issue. I'll help take a closer look and continue assisting you from there.
Roku Community Manager