I'm using the ConbeeII stick on a RPi3 and recently a few of my zigbee devices has just dropped out of the zigbee network. Only battery powered devices from what I can tell. I can delete them and add them again, and then they work for some time, maybe hours, maybe days, but they all just stop reporting any status updates.

I thought perhaps updating ConbeeII to the latest firmware would help, but it appears it didn't.

Anything I can do to fix this? Other than buying a new stick of a different brand?