Chromecast Audio - Excessive data traffic?

Hi
I just bought and installed two Chromecast Audio devices on my WiFi network. They work great for listening to the same music from room to room. But, the weird thing is, they generate loads of data to my router, even when I'm not casting. These things are in permanent Tx mode. What's going on? I've Denied them access to my router til I find out. And I'm looking at putting in a Monitoring Mode USB sniffer to check the traffic.
Anyone else seen this problem? Any ideas?
Thanks for reading....

Chromecast Audio - Excessive data traffic?

from Android Authority Forums http://ift.tt/2kgnPYn
via IFTTT