Again, I think that it would be much better if the interference discussion could be moved to that other thread since that i not specific to this dongle as it applies to all Zigbee dongles and devices, and would be better if questions and feedback on the suggested best practice in that guide were collected here instead → Guide for Zigbee interference avoidance and network range/coverage optimization
But for reference read this whitepaper PDF from Intel on usb.org → https://www.usb.org/sites/default/files/327216.pdf as see this video (that is posted there) about how extremely sensitive Zigbee really is, and understand that just because it works does not mean that it works well, as for example battery powered devices will draw much more battery if they have to resend messages due to interference, so a common symptom of interference a “seemingly working” Zigbee setup is that batteries last only for weeks or months instead of for years:
