[dns-operations] recursive glueless handling by 8.8.8.8

[Dave Lawrence]

Calvin Browne writes:
> does anyone here know how 8.8.8.8 handles recursive glueless situations?

The Google folks are on the list and undoubtedly will answer, but I'm
still curious about what even prompts the question.

If it's actually missing glue -- NS records that are under the
delegation point -- and the delegating NS RRset does not include any
independent NSs, then the protocol itself doesn't have an intrinsic
mechanism for forward progress.  A resolver should SERVFAIL its
client, perhaps with the "Code 22 - No Reachable Authority" extended
error code.

Are you seeing something that suggests Google DNS is making some
additional effort to continue?