Had the same at my in-laws place, they had issues and we wired to them. That fixed it but then they had another issue with the box, the stupid engineer removed the cable and the original fault returned! Next time I was down I put it back to hardwired, no issues since.
Only reason I can think they don't want you hard wiring it is because each box creates their community open WiFi!?
Don’t think so. Different zigbee profiles.
Unlikely. While some of them use zigbee as the transport layer, the protocol is not ZHA1.2 (or zigbee 3.0 for that matter). @mike.maxwell would know for certain.
Edit: Ha! @marktheknife got there first!
Just an update on my situation.
I changed zigbee channel from 20 to 15 yesterday morning.
To my pleasant surprise most of my zigbee devices connected up OK to the new channel with no intervention from me.
The only ones that required re-pairing were Sonoff, Aqara and Xiaomi devices.
Last evening and today everything has continued to work OK so my initial experience is good. Changing channels has done the trick. Fingers crossed. 
Just a quick update should people care to know.
It's been 9 days since I changed the zigbee channel and things are ticking along nicely. No strange delays etc. YAY!!!!!!!! 
I'm getting one installed next week so reading through this and going to switch channel in advance... Just need to avoid sonosnet and my own 2.4ghz WiFi which I need for some devices
Download the Hubitat app
