I hit this again today.  Again I am using the WIDE dhcpv6-client package.  I have been shuffling my 2 ISPs (I have one for backup) and this morning I got an IPv6 address/prefix initially but then when it got close to expirationI wasn’t able to renew.  

Stopping SQM scripts fixed this immediately.

I’m willing to help troubleshoot if someone else is willing to look into this.  I have SQM off for now :(

Thanks.