I was able to include this without issue to a C8 and a C8 pro.
Same firmware as yours as well.
Is it possible that another device was in join mode and that that device produced this error?
2 Likes
I am not aware of any other devices in pair mode when I was trying to join the Philips Hue motion device but there is something preventing it from fully pairing/configuring. But, to your idea that another device was in join mode may be part of my issues. Sometimes, but not often, I have other devices stop working and if I go to the hub's add a device it will find it add it back as a previously paired device. I don't know why this happens but fortunately its a rare occurrence.
I pulled the Hue Motion sensor out and tried to pair it again, and low and behold it paired right away and seems to be working. Very odd.
Thanks for getting back to me on this. At least I can put it into service now instead of making it a paper weight. 
