If you have a machine that is behind a NAT or the IP address the relay/server gets doesn’t match any of the registration IP addresses that the client sends up in its registration request, there are a few inspectors that will not have a value to return as the server has no idea what the actual IP address is.
Think of a case like this. Client is behind NAT and uses 10.1.1.1 as its address and then registers with a relay on the other side of its NAT and thus it uses the router/NAT address which is 192.168.1.10 so the infrastructure thinks it registered as that address. The Client used 10.1.1.1 on its registration but as that’s not an IP address that matches what the client actually came in on the reply to the registration is not able to give back the address that was registered on.
This inspector is supposed to be able to help distinguish which of the 10 NIC’s you have did you actually register over but it depends on the receiving end (the relay) being able to give an IP address it is communicating over to the server that matches the registration request.
Do any of these scenarios apply in your case? It doesn’t seem to be if they are on the same subnet unless there is some strange routing going on.
I’d look at your logs as to what the information going up in the registration command is as if that information isn’t valid its possible that the endpoint has some strange configuration that doesn’t match the reality of the network.