Videos in event list disappear

Hi

The videos in the event list disappear. Why ? I can see all the events in the video history. I am able to see the videos in the event list shortly after it's being recorded, but they will disappear later on during the day.

For example, in the first picture you can see they're events detected around 3-4 O'Clock AM. In the 2nd picture, the videos only start at 6h33 AM in the event list. In the 3rd picture taken later during the day, the videos start at 12h14 PM. What happened to the videos between midnight and 12h14PM?