Ah...um?
I'm no DNS expert, but shouldn't they be authoritative for their own DNS server?
nslookup 1.1.1.1 1.1.1.1
Server: 1.1.1.1
Address: 1.1.1.1#53
Non-authoritative answer:
1.1.1.1.in-addr.arpa name = 1dot1dot1dot1.cloudflare-dns.com.
Authoritative answers can be found from: