I reproduced the problem with:
ii isc-dhcp-client 4.2.4-7ubuntu12.8 amd64 ISC DHCP client ii isc-dhcp-common 4.2.4-7ubuntu12.8 amd64 common files used by all the isc-dhcp* packages
After adding the proposed repo and updating isc-dhcp-client and isc-dhcp-common to:
ii isc-dhcp-client 4.2.4-7ubuntu12.9 amd64 ISC DHCP client ii isc-dhcp-common 4.2.4-7ubuntu12.9 amd64 common files used by all the isc-dhcp* packages
the problem was fixed and all IPv6 DHCPv6 interfaces successfully were configured with their IPv6 addresses.
I reproduced the problem with:
ii isc-dhcp-client 4.2.4-7ubuntu12.8 amd64 ISC DHCP client
ii isc-dhcp-common 4.2.4-7ubuntu12.8 amd64 common files used by all the isc-dhcp* packages
After adding the proposed repo and updating isc-dhcp-client and isc-dhcp-common to:
ii isc-dhcp-client 4.2.4-7ubuntu12.9 amd64 ISC DHCP client
ii isc-dhcp-common 4.2.4-7ubuntu12.9 amd64 common files used by all the isc-dhcp* packages
the problem was fixed and all IPv6 DHCPv6 interfaces successfully were configured with their IPv6 addresses.