This is exactly what I did too. And by doing openstack router add port Flat1-Router flat1-rtr-port You are effectively plugging also IPv6 subnet to this router which shouldn't be possible (and it's not when You plug subnet "directly" to the router by doing "neutron router-interface-add <router-id> <subnet-id>".
Hi Peter,
This is exactly what I did too. And by doing openstack router add port Flat1-Router flat1-rtr-port You are effectively plugging also IPv6 subnet to this router which shouldn't be possible (and it's not when You plug subnet "directly" to the router by doing "neutron router- interface- add <router-id> <subnet-id>".