FYI, there is another known design flaw with length of the USB port on dongle that can also be related
- To avoid EMF interference strongly recommended buy and use → Long USB extension cable
- Another reason for using a USB extension cable is that the USB-plug design of ITead’s Sonoff Zigbee 3.0 USB Dongle Plus hardware adapter is a little short which makes it harder and sometimes impossible to plug it into some USB ports if the computer enclosure/chassis/casing is to thick around the USB-port as that will physically prevent the USB dongle from actually making a proper connection inside the USB port even if it looks like it is plugged in all the way that is possible.
Tip is also to use in it in a powered USB 2.0 hub as USB 3.0 can cause serious interferece to Zigbee.
Regardless, be sure to follow setup tips and best practices as Zigbee is very sensitive to interference:
https://github.com/home-assistant/home-assistant.io/pull/18864/commits/970295a277e8f01d3ee39eeeaacf453625b988d3 from → https://github.com/home-assistant/home-assistant.io/pull/18864
and