The address listed is the same as the "LAN IPv6 Address" in IPv6 settings and is the prefix to all my ipv6 addresses. Also in those IPv6 settings "Connect to DNS Server automatically" is set to disable, and both pi-hole ipv6 addresses are listed in IPv6 DNS Server 1/2. So I'm not really sure how to further specify clients use the pi-hole ipv6 addresses for DNS. I would think with those settings, even if the router's IPv6 was used, it would be passing along the pi-hole ipv6 addresses.
