OK, so here's the scoop on these, per Third Reality:
The button has two zigbee pairing modes, the standard ZigBee pairing mode is used to pair most ZigBee hubs such as hubitat, while the Echo ZigBee pairing mode is specifically used to pair to Amazon Echo speakers.
If the button is in standard Zigbee pairing mode, the LED indicator will blink quickly in blue. If the button is in Echo ZigBee pairing mode, the LED indicator will blink quickly in blue and red.
In versions before 1.00.22, to change between 2 ZigBee pairing modes, press the front button and reset button simultaneously for 5 seconds.
In versions 1.00.22 and later, to change between 2 ZigBee pairing modes, press the reset button 5 times within 5 seconds.
So the unit I had was initially blinking red and blue.
When it joins Hubitat in this mode, only one button event is registered and the wrong driver gets selected.
After changing the pairing mode, the correct driver is selected and the device functions as expected.
Button headed back your way...
