Siri not working on my tvos remote

Wondering if I have an issue with the tvos remote that came with my developer kit. When I press the Siri button, I get a prompt telling me to hold down the button while I speak. It then scrolls through a list of suggestions. However, pressing and holding the Siri button doesn't do anything - it's not reacting to speech. I've checked that Siri is enabled in my Settings. Any ideas?

In my case Siri starts to listen when I connected Aurio Output device to Apple TV.

My display does not have speakers, so audio signal comming through HDMI is not played back. When I connect Bluetooth speaker the Siri starts to listen and process my voice commands.

Siri not working on my tvos remote
 
 
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