Motion Alerts Inconsistent

We have the motion zone on our Doorbell Pro configured to include our driveway. We have noticed that it alerts when we back out of our garage into the driveway (that is expected). However, there is no alert, it is not triggered, when we pull into the driveway. The only time it did so was at night, and I suspect it was because of the headlights triggering the motion detection.However, we had a delivery driver pull into the driveway at night, which did not alert the system. The driver got out of the car and walked to the front door, which also did not alert the system. We only received an alert when the delivery person rang the doorbell.This is not what we expected and not what we desired from the system. It should be alerting when someone pulls into our driveway, based on how we have the motion zones set.Cars passing the house at night (headlights on) often (though not always) trigger the alerts as well. Any suggestions?