SenorNaddy: This is what I get from syslog on the OpenWRT firmware on my router. This was previously working fine, and just stopped working without me making any configuration changes. I was able to run a tcpdump on the wan port (so I can see ppp headers etc) and I see the request get sent out, but it never receives a response.

May 5 12:30:20 internet daemon.debug dhcp6c[1144]: copy_option: set client ID (len 10)
May 5 12:30:20 internet daemon.debug dhcp6c[1144]: copy_option: set rapid commit (len 0)
May 5 12:30:20 internet daemon.debug dhcp6c[1144]: copy_option: set elapsed time (len 2)
May 5 12:30:20 internet daemon.debug dhcp6c[1144]: copyout_option: set IA_PD
May 5 12:30:20 internet daemon.debug dhcp6c[1144]: client6_send: send solicit to ff02::1:2
May 5 12:30:20 internet daemon.debug dhcp6c[1144]: dhcp6_reset_timer: reset a timer on pppoe-wan, state=SOLICIT, timeo=37, retrans=121632
While this never specifically states an error, it does show that the router is attempting to request a prefix, but still never receives one

Noodles: Seems to be fixed now

Noodles: Magically fixed. I think it was a problem at Snap's end. I haven't changed anything on my end.