For anyone finding this in 2024, I had to enable "Multicast Enhancement" for the Unifi Wifi network AND I had to disable Hotspot 2.0. Only then did the Router Advertisements flow down to wifi clients. I was sitting in wireshark on a MacOS 14.6 laptop client and suddenly there was a flurry of traffic.
Pro-tip: You may have to wait for the RA interval for the Unifi change to make a difference. Default is 200 seconds, you can change this in the RA Server settings. I set mine to 10 seconds then clicked the button to restart the RA server.
This worked!
Screenshot 2024-11-06 084436.png
Screenshot 2024-11-06 084835.png