networkd: Delegated prefix advertised only once?

[Radosław Kintzi <radek@xxxxxx>]

Hello. 

I'm not sure if this is the right place to ask this sort of question, but I'm
having trouble configuring my router for a home network. Here is the setup:

My ISP provided me with a usual "router" that acts as a modem, router,
hotspot, and switch all in one. I will refer to this device as a Wi-Fi device
to differentiate it from the router I am trying to set up. The router is
a small PC with four Ethernet interfaces. It runs Archlinux (fresh
installation) with Systemd 256.6. The router is connected to the Wi-Fi device
using an Ethernet cable.

There is also a third device, a laptop with an updated Archlinux, which I will
refer to as a client. It is connected to the router using Ethernet cable.

My ISP supports IPv6 prefix delegation; however, I'm struggling to make it
work correctly. The problem is that the client device only acquires an address
from the delegated network when the networkd daemon on the router is
restarted. If the client is unplugged and then plugged back into the router,
or if its network daemon is restarted, or the `networkctl reconfigure enp*`
command is executed, it fails to assign an address to the interface.