Iris Motion Sensor Won't Join

I had something very similar occur with a completely different Zigbee device that was working and I inadvertently removed it from the IDE. I would get visual confirmation it would reset and pair every time, but no device was ever added. I saw the zbjoin event as you did and I even tried manually creating the device and entering the Device Network ID and Zigbee ID from that event along with the appropriate device handler. I stumbled upon the following post and ended up modifying the device handler and adding

device.endpointId = 1

just before every Zigbee method called within the code. That fixed it for me.

My Iris Motion Sensors are using the SmartSense Motion device handler. You could try adding it and doing what I did.