Thanks for the advice. We are AMX dealers, my guy is on site now. AMX got back to us and suggested a few things. We are already running the most recent publicly available firmware on both the R4s and Zigbees, but they said they have a newer version that may address the issue that they haven't made available yet. We're going to give that a try. They also recommended disabling Bonjour on the Zigbees. Fingers crossed. This customer was so frustrated he actually broke the screen on one of his R4s by pounding on it with his finger trying to get it to work.