The DNS naming confusion was largely dealt with by having a small number of TLDs and rarely referring to complex things like partially specified subdomains, but every once in a while a fool named their machine com, org, or net. (Though these as subdomains were far more toxic.)

If I understand correctly, the scenario is an internal machine named "george", which is being properly search-pathed and looked up as "george.example.org." with nothing leaking anywhere, becoming vulnerable to Walmart being able to issue certificates in the name "george", because the DNS client library's search pathing is not read out by the layers that simply know the machine as "george".

I'm not totally convinced by the premise here that certificate checkers never read out the final fully-qualified domain name from getaddrinfo().