Traffic graph doesn't show hostnames

[jeskeca]

I have the traffic graph set to hostnames, and the table header says "hostname or IP", but it shows all IP addresses, even though these IPs have hostnames in the DHCP table.

Is this a bug? Is there something I have to do to get it to resolve the local IPs in the dhcp table?

In these screenshots you can see that 192.167.2.2 has the hostname "JeskeTahoeW520", but only the IP is displayed in the traffic graph.

https://www.dropbox.com/s/zk3l2fyiez34ijh/Screenshot 2017-10-21 10.10.01.png?dl=0

https://www.dropbox.com/s/xfqvdpwrmf76w1i/Screenshot 2017-10-21 10.11.10.png?dl=0