I assume you're on the latest 103 firmware?
Yeah, I discovered this same issue early this past week... Not knowing if it was a failing radio on my C7 or a firmware issue, I decided to roll the dice & do the C8 migration Friday night (migration went smoothly overall).
I let zigbee settle in overnight, then updated to 103 Sat morning and tried to do some zigbee pairs (I had 2 latest-gen Hue bulbs to pair direct)...
I first tried a spare Centralite plug as an easy "known entity" test, and that went great -- all as-advertised. I did 1 Hue bulb, and that also went pretty smooth. But the second Hue bulb was sketchier -- it took a few tries, but eventually it paired too.
I do think there's something amiss in the Hubitat's firmware though -- there have been a few posts this past week in the community here all related to similar zigbee join/pairing issues.
I don't know if v103 was the silver bullet or I just somehow got lucky with those pairings yesterday, but finagling that last Hue bulb didn't inspire confidence -- I'm glad I don't have any more pairings to do in the near future!
