Fibre installed yesterday.  Using the USG3 with VLAN tagging etc.  Works well IPv4.  My settings for IPv6 look as per the recommendation, but it appears to me I'm not getting any delegation at the USG/WAN level, and no allocation of IPv6 at the LAN level either.

I've set the WAN interface to DHCPv6, and prefix delegation size to 56.  As noted it's getting an IPv4 address and working fine, so I assume it's only the IPv6 config I have an issue with.

On the LAN side, I see that you need a proper delegation configuration that connects to the WAN setup - I have a LAN configuration with prefix delegation set, prefix id 62, everything else pretty much as per defaults. There is a second LAN, with a different prefix id, I don't think that's causing the problem.

I can see the configuration file on the USG itself: /var/run/dhcp6c-eth0.10-pd.conf

Nothing I can obviously see wrong, but I seem to have no IPv6 on the WAN interface, and nothing obviously wrong in the logs.

To me it's a bit worrying that /var/log/dhcp6c.log is consistently empty.  I occasionally see in there a message about exiting, but the process is still running.  I tried running with -D to see any logging, but still nothing material in the logs.

Is there anything obvious I should be doing here to debug?  Ideally I'd see a dhcp request and some sort of reply, but short of Wireshark I'm seeing nothing at the moment. Hoping there's an obvious misconfiguration.