Video doorbell 3 skips several Person motion notifications & recordings

Video doorbell 3 (battery) is skipping to notify and record Person Motion… Several person motions are missing during each day of using the doorbell… Sometimes it does notify & record someone leaving or approaching the door, but on many other occasion it completely ignores, but notifies and records leaves moving on the tree across the road, I have set it correctly, because it used to work perfectly the first month…but now seems to skip several Person movements…daily.. Any idea what to do?