Zigbee2mqtt report no link quality value

I’m using an IKEA Tradfri bulb model LED1836G9 with zigbee2mqtt (via CC2531 dongle).
The bulb is close to CC2531 (about 1.5 mt.) but home assistant is reporting link quality equals to zero.
This is in example of zigbee2mqtt log:

info  2020-08-04 10:20:40: MQTT publish: topic 'zigbee2mqtt/luce IKEA', payload '{"state":"OFF","update_available":false,"brightness":0,"linkquality":0}'

I’ve also a zigbee switch IKEA E1743 reporting correctly the link quality value.
The bulb and the switch are updated to last available firmware.

Is the bulb not completely supported by zigbee2mqtt?

Thanks in advance

What version of the firmware is installed on the CC2531 ?

{'type': 'zStack12', 'meta': {'transportrev': 2, 'product': 0, 'majorrel': 2, 'minorrel': 6, 'maintrel': 3, 'revision': 20190608}}