I see the same. Still see those prefixes via direct peering, but DFZ doesn't have them. Their auths are not reachable even though I have routes for them.

Some other weirdness I'm poking a bit on that doesn't seem like it could possibly be related to FB DNS though.

On Mon, Oct 4, 2021 at 12:39 PM Hugo Slabbert <hugo@slabnet.com> wrote:

Looks like their auth DNS dropped out of the DFZ:

https://twitter.com/g_bonfiglio/status/1445056923309649926?s=20
https://twitter.com/g_bonfiglio/status/1445058771261313046?s=20

--
Hugo Slabbert

On Mon, Oct 4, 2021 at 9:21 AM George Metz <george.metz@gmail.com> wrote:
Also impacting Instagram and, apparently, WhatsApp.

On Mon, Oct 4, 2021 at 12:05 PM Eric Kuhnke <eric.kuhnke@gmail.com> wrote:
>
> https://downdetector.com/status/facebook/
>
> Normally not worth mentioning random $service having an outage here, but this will undoubtedly generate a large volume of customer service calls.
>
> Appears to be failure in DNS resolution.
>