Ring video doorbell pro not recording motion at night

During the day the video captures multiple motion episodes as people walk past the house but there are never any episodes between about 9pm and 8am despite our paper being delivered at 5am and the dustbins emptied at 7am neither are recorded. It is obviously working well during the day time and it looks on the history view as though it is recording all night but there is never any history at night. Is this a setting issue or a fault? This was installed 3 weeks ago and set to record motion with people only.