Same, this address for me is also gmail.

This is what Gmail shows me from earlier today, when the SPF record was not present : 

Message ID <bff409fd0177c9caf1461e243969163a@polarismail--com.w.emailarray.com>
Created at: Thu, May 16, 2024 at 11:59 AM (Delivered after 77 seconds)
From: "Scott Q." <qmail@top-consulting.net> Using Group-Office
To: Michael Thomas <mike@mtcc.com>, nanog@nanog.org
Subject: Re: Mailing list SPF Failure
SPF: NONE with IP 50.31.151.76 Learn more


Message ID <74b33cf0-b7c4-46ac-8154-1cfca082eff4@mtcc.com>
Created at: Thu, May 16, 2024 at 2:13 PM (Delivered after 85 seconds)
From: Michael Thomas <mike@mtcc.com>
To: "Scott Q." <qmail@top-consulting.net>, nanog@nanog.org
Subject: Re: Mailing list SPF Failure
SPF: NONE with IP 50.31.151.76 Learn more
DKIM: 'PASS' with domain mtcc.com Learn more


Message ID <20240516190341.BEB6F8B534F1@ary.qy>
Created at: Thu, May 16, 2024 at 3:03 PM (Delivered after 79 seconds)
From: John Levine <johnl@iecc.com>
To: nanog@nanog.org
Subject: Re: Mailing list SPF Failure
SPF: NONE with IP 2001:1838:2001:8:0:0:0:20 Learn more
DKIM: 'FAIL' with domain iecc.com Learn more
DMARC: 'FAIL' Learn more

All 3 of these messages were delivered to my inbox as normal. The messages from Scott and John provided warnings when hovering over the icon that the user was not authenticated.


After the SPF record was fixed : 

Message ID <de75db23-c166-095c-a2ad-2f3a7e613409@iecc.com>
Created at: Thu, May 16, 2024 at 10:36 PM (Delivered after 68 seconds)
From: "John R. Levine" <johnl@iecc.com>
To: "Scott Q." <qmail@top-consulting.net>
Subject: Re: Mailing list SPF Failure
SPF: PASS with IP 50.31.151.76 Learn more
DKIM: 'PASS' with domain iecc.com Learn more
DMARC: 'PASS' Learn more

Message ID <e47a1819deae8e7c8f592ab653c424d5@polarismail--com.w.emailarray.com>
Created at: Thu, May 16, 2024 at 10:23 PM (Delivered after 180 seconds)
From: "Scott Q." <qmail@top-consulting.net> Using Group-Office
To: "John R. Levine" <johnl@iecc.com>, William Herrin <bill@herrin.us>
Subject: Re: Mailing list SPF Failure
SPF: PASS with IP 50.31.151.76 Learn more

The warnings were not present on these messages .

Google's support page if you click on those warnings it here : 

https://support.google.com/mail/answer/180707

Where it states the following : 

Check if a message is authenticated

Important: Messages that aren't authenticated aren't necessarily spam. Sometimes authentication doesn't work for real organizations who send mail to big groups, like messages sent to mailing lists.


On Thu, May 16, 2024 at 10:46 PM Michael Thomas <mike@mtcc.com> wrote:

On 5/16/24 7:36 PM, John R. Levine wrote:
> I think a lot of us have nanog whitelisted or otherwise special cased.

I don't and gmail is my backend. That's trivial falsification that lack
of an SPF records alone will cause gmail rejects.

Mike

>
> Also, it's been pumping out list mail for decades and I expect has a
> close to zero complaint rate so even without the SPF ths IPs it sends
> from have a good reputation.
>
> On Thu, 16 May 2024, Scott Q. wrote:
>
>> I'm surprised nobody noticed for close to 10 days. I was away
>> from work and upon coming back I saw the little discussion there was ,
>> in my Spam folder.
>>
>> On Thursday, 16/05/2024 at 18:56 John R. Levine wrote:
>>
>> On Thu, 16 May 2024, William Herrin wrote:
>>> The message content (including the message headers) is theoretically
>>> not used for SPF validation. In practice, some SPF validators don't
>>> have direct access to the SMTP session so they rely on the SMTP
>>> session placing the envelope sender in the Return-path header.
>>
>> But that wasn't the problem here, the SPF record was just
>> gone.  Oops.
>>
>> I see that the SPF record is back and seems have the correct addresses
>> so we can now return to our previously scheduled flamage.