> I did have a brief power failure the other evening, which restarted
> the cable modem but not the gateway router.  I noticed that dhcpleased
> re-started the IPv4 lease, but I had to manually issue `$ dhcpcd -n vlan3`
> to re-establish the prefix delegation.  I already have ifstated running
> on the gateway, so I may just add that to the script.

Bingo. That's due to the aforementioned bug. As stated, once Roy reverts
the problematic commit in master, I'll post on this chain for Stuart to
update the port to master.