Our domains aren't resolving with 1.1.1.1, but do via DHCP

The DNSSEC configuration on your domain registrar, Domain.com, LLC, is incorrect:

The DNS resolver that is supplied to you via DHCP isn’t validating DNSSEC.

Same goes on with other large public DNS resolvers, such as e.g. Google Public DNS, OpenDNS and Quad 9.

The DNSSEC failure you have between your registrar, Domain.com, LLC, and name server operator (my-nameservers.com), is preventing the proper DNS resolution through DNS resolvers that validate DNSSEC.