I’ve got some Nanoleaf Thread bulbs, with the xxx-xx-xxx pairing codes.
My Google Hub is set as Preferred Network in the Thread integration.
When I add the bulbs to the Nanoleaf app they become visible in HA but after pressing Add and entering the 8 digit code it says “This accessory is already paired to another device. Please reset the accessory and try again”
I assumed this was the Nanoleaf app but after deleting it I get the same result.
I was having the same problem last week. what worked for me was setting up the bulbs next to my HA server. I am running as 2012 mac mini on bare metal. Before i was using my cell phone from the other side of my house and I was only able to pair 1 of 6 of my old homekit bulbs. Moved setup to my server and added the rest in a flash.