Secondary channel on an Evalogik 2 channel outdoor switch keeps going off line

I just installed an Evalogik 2 channel outdoor switch and the secondary channel keeps going offline. I’ve tried deleting and reinstalling several times, the device is correctly recognized and works initially but once the secondary switch is ‘turned off’ for about 20 minutes that switch goes offline. The primary switch stays on line and using the control button on the switch to turn the light on restores the connection.
Is this a known issue or do I have a faulty switch?