Welcome to the user community, @andyfurno!
Unless you have a Cam Plus license assigned to that camera, your captures will be limited to a 12-second event recording every 5 minutes. So if someone walks by within 5 minutes after a trigger, a notification will not be generated for them.
You should use your detection sensitivity and zone to eliminate as many shadows and tree movements as you can. If the person is a reasonable size in the overall frame, then you may be able to take the detection sensitivity down to 1. That should eliminate a lot of smaller triggers.
Also, add a SD card, and put it on continuous record. That will keep at least 3 days of coverage available for you to review, extending any events you get.