Actually - I found this handy information:
they are failing SPF alignment . The domain used in the “MAIL FROM” portion of the SMTP transaction is “infusionmail.com”. The domain used in the “From:” header of the email is “themarkofmastery.com”. Therefore, even though SPF passes (infusionmail.com authorizes IP addresses within the 35.227.130.0/24 range), it fails DMARC’s alignment requirements.
DMARC requires that either SPF or DMARC passes and is aligned, not both. Infusionsoft is DMARC-compliant through the use of DKIM, which does pass alignment (as shown in your DMARC report). We will not pass DMARC’s SPF alignment test since we do not use your domain as the sending domain during the “MAIL FROM” portion of the SMTP transaction. This is intentional - the “MAIL FROM” email address is also the “Return-Path” address where bounce notifications are sent, which allows us to remove invalid email addresses from your list to preserve your (and our) deliverability.
on this post: Failed SPF infusionmail.com IPs
I believe that explains the issue.