I tried a setup with my phone and only one PC as a roon server/controller. I used internet access from my phone through USB tethering to the PC. There was only one zone - the PC sound card. Also with this simplest setup there was no change in behaviour of roon radio.
We’ve made an update to our servers that we believe will help improve this. Can you give this another try and let us know if things are working for you now?
Your patience as we’ve looked into this has been greatly appreciated — Thanks!