Francis, thanks for your feedback. The dongle is plugged directly on the USB port on the khadas board. and I had the sensor located at less than 3 meters of the dongle.
Anyway , after performing a second, then a third pairing, I have finally both sensors reporting temperature changes !
@Hedda: Thanks for the feedback and providing the link to your great Zigbee interference guide !
The malfunctioning devices were less than 2 meters from the Zigbee dongle, so it could not be a range issue.
As mentionned earlier, I finally managed to get the devices reporting the temperature, however one is still not reporting the humidity …
I am quite puzzled with a mention in the guide:
While both ZHA and Zigbee2MQTT do support older Zigbee Coordinator adapters based on the old Texas Instruments CC253x (CC2530 and CC2531) they are not recommended any longer, so spare yourself the potential grief and instead just buy a newer Zigbee Coordinator adapter from the start.
I have bought quite recently the Sonoff Zigbee 3.0 USB Dongle Plus , and yet HA indicates the coordinator to be Texas Instrument CC253x ??? (see screen copy below.)
Do you think I get an outdated firmware on this Dongle ? Should I try to upgrade the firmware ?
Such pairing issues symtom are common when have interference and usually due not using a USB extension cable to get it away from the computer and other devices + make sure connecting it to a USB 2.0 port and not to a USB 3.0. Read and try to follow the linked guide, it mentions this several times and even has a video showing an example of how the radio adapter behaves when too close to the board.