Streambar powered off but still sends MDNS packets?

Hi All,

I have a Roku TV and a Streambar (not the Pro model). The Streambar is in soundbar mode only. Even 24 hours after "turning off" the two Roku devices with the remote, I see the Streambar sending out MDNS query packets to IP 224.0.0.251. Would anyone know the reasoning behind this? Depriving the Streambar of electricity seems to be only way to stop these wi-fi transmissions.

Thanks.