Where are you based? I can check if this can be replicated in our backbone, in case we have a PoP close.

On Sep. 6 2019, at 11:17 pm, Nick Hilliard <nick@foobar.org> wrote:
Nick Hilliard wrote on 06/09/2019 21:19:
Chip Marshall via NANOG wrote on 06/09/2019 20:11:
Hello, I'm seeing an oddity when doing DNS lookups for www.google.com
from our
London datacenter, and I'm curious if other people are seeing the same
behavior.

I saw a bunch of monitoring systems queries for www.google.com/A return
back with no A records at ~20:35 BST.  It's returned back to normal now,
but we needed to flush a bunch of DNS caches.

... aaaand there we go again at 22:07 BST.

Nick