Why does Web GUI on media port fail to work when configured with a single IP from scratch?

Hello,

I know that I can enable the web management interface on a media port by configuring the HIP IP List under network-interface and mapping the corresponding realm of that network-interface to the http-server.

However, while running some tests over the past few days, I unexpectedly noticed that if I only have a single IP address from the very beginning, I can't seem to successfully enable the web management interface on the media port.

Here is what I tested:
I initially assigned an IP to wancom0. After logging into the web interface, I removed the IP from wancom0 and assigned it to the network-interface instead—making sure to set up both the hip-ip-list and the http-server as well and reboot.