Hi,
external-content.duckduckgo.com does not resolve for me when using your family filter DNS.
# host external-content.duckduckgo.com
Host external-content.duckduckgo.com not found: 3(NXDOMAIN)
Running the standard test on dnsleaktest.com I get the following:
155.138.200.217 dns-edge-usa-east-atlanta-v.cleanbrowsing.org. Choopa, LLC Atlanta, United States