So instead of this:
    - network:
        container_bridge: "br-vlan"
        container_type: "veth"
        container_interface: "eth12"
        host_bind_override: "eth12"
        type: "flat"
        net_name: "flat"
        group_binds:
          - neutron_linuxbridge_agent

it should look like this?
    - network:
        container_bridge: "br-vlan"
        container_type: "veth"
        container_interface: "eth12"
        host_bind_override: "enp1s0f0.718"
        type: "flat"
        net_name: "flat"
        group_binds:
          - neutron_linuxbridge_agent