Receiving DMARC reports for emails I do not send

I have finally figured out why I was seeing these DMARC reports about properly signed email sent from my domain.

As I mentioned in the question, my DMARC record was "v=DMARC1; p=none; pct=100; sp=none; rua=mailto:[email protected];"

By default, Google apps will not deliver emails sent to [email protected] to any of your mailboxes. In order for me to receive these emails I had to create a group with the same name and add myself as a member of this group. This setup step is explained in this Google Apps Help Page.

Turns out however that the email forwarded by the group to my mailbox was counted as an email sent from my domain which meant that I also received a DMARC report for it. This created a feedback loop so I received a DMARC report every day because a DMARC report was forwarded the previous day.

Once I created a new account called [email protected] to accept the DMARC emails and changed my DNS records to "v=DMARC1; p=none; pct=100; sp=none; rua=mailto:[email protected];" the problem went away.