Please follow the below template, it will help us to help you!
Domains on the block list should be blocked even over IPv6.
I have full IPv6 connectivity to the internet and my PI Hole (which is working wonderfully for IPv4 thank you) is not blocking domains over IPv6.
Resolving www.google-analytics.com I get two entries in the query log IPv4 says Pi-holed IPv6 says OK (forwarded).
I have run pihole -r again to ensure both IPv4 and IPv6 blocking is enabled.
I have also ran sudo apt-get upgrade to ensure I am running the latest version of Raspbian Jesse Lite.