Its a bit late, but maybe someone is still having the problem (I was until today).
I bought two Tradfri Led 1055lm Ikea bulbs. I have a Conbee 2 as my cordinator connected to HA via ZHA.
I was able to “pair” the bulbs to ZHA by turning them on and off 6 times and then looking for devices, but after a couple of seconds they became unresponsive to any command. I found out today that if right after the bulb was detected by ZHA and before it became unresponsive you cut the power to the bulb it is correctly paired.
Hope it helps someone, cheers.