Office 365 Admin - How to see what policy was triggered

I am an admin for a 365 site.

I received an email that was not sent to me nor CCed. It looks like I am in the BCC so we are not sure how the email came to me.

I am wondering if there is a policy somewhere that triggered this. Is there a way I can back-trace the email to see if an event was triggered or a policy was invoked for me to get a BCC of this email?

I tried Mail Trace, Mail Flow and Rules but there is nothing there .