Not picking up motion directly in front of Ring Doorbell 3

I have my ring doorbell 3 directly above my mailbox , when I had mail delivered today they would have entered 2 zones and stood directly in front of my mailbox and I did not receive a motion detection notification or any footage. When I opened my door and reached to grab my mail (door is right next to mailbox) I received a notification and footage. Wondering why I didn’t receive anything for when the mail person entered my yard and stood directly in front of my doorbell.