Doorbell V2 detecting moving tree shadows at night

I want the doorbell to detect only people, but at night it detects shadows cast on the porch by a tree as cars go by. I have lowered motion detection sensitivity to 15, enabled smart detection events and selected only person on the Custom Recordings screen, but it still records many videos as cars go by. Interesting it only sends a notification when it detects a person, so it can tell the difference. Am I missing some setting?