Missing video footage on battery door bell

Noticed that I am randomly missing video footage normally late evening or at night. It’s not happening everyday, sometimes it works perfectly, It will work fine for a few days, then I might not get any notifications if say my son comes home late in the early hours. Sometimes it hasn’t even picked up the motion of us parking the car on the drive and walking up to the front door. Surely it should pick up the motion of someone either leaving the house, or walking up to the front door, even if the bell isn’t pressed?