Help with Unknown IPV6 Device/Address

Hi,

I've got NextDNS setup on my Windows,Mac and Linux machines, and all this is working great.

The only issue is that just 1 of my devices is showing in the logs as "Unidentified". I know what the machine is as I know it's  IPV6 address. However I can't get it to display the name when it's going over IPV6. Its' IPV4 traffic is correctly named as I've appended it to

https://dns.nextdns.io/XXXXXX/MyMachineName

How can it get it to show up with the MyMachineName for IPV6 traffic?

Am I missing something?

I've attached screenshots