DirecTV Stream remote control | Denon AVR won't power off

I am running all of a home's media through an Atlona Pro3 UHD66 Switcher (last device downstream). It's working flawlessly.  I've successfully configured a DirecTV Stream remote to Power ON a Samsung QLED TV and Denon AVR-x3300w with no issues. The Denon volume control is working and, again, the DirecTV Stream remote powers it on. However, when powering down from the DirecTV Stream remote, the Denon does not turn off. All devices are on running clean on network. Samsung is wireless. DirecTV Stream device, Denon, and Atlona are all hardwire ethernet.

Connections: DirecTV Stream device HDMI  output > Denon AVR HDMI input (Cable/Sat) > Denon ARC output > Atlona HDMI input 1

All HDMI cables are Ultra-Speed/Ethernet equipped. Suggestions?