If dhcpv6-options is configured without requesting a DHCPv6 address or PD, the DHCPv6 client runs with an empty configuration. This is because the dhcpv6pd variable on line 1106 of python/vyos/ifconfig/interface.py is assigned an empty dict.
To reproduce boot the ISO and configure as follows:
set interfaces ethernet eth0 dhcpv6-options commit
Verify dhcp6c is running by running ps ax | grep dhcp6c.