Cameras with PIR sensors can pick up heat from non-human objects within the field of view as well.  For example, trees or swaying objects under sunlight.

Fix 1: Customize the area to allow for thermal and motion detection in some areas

1. Login to Setup > Main Menu > Alarm > Detection.
   
   
2. Click on the Gear icon beside the Channel number you want to customize.
3. Deselect the areas where the false triggers (trees or swaying objects) are.
   
4. Right-click the mouse to exit that page.
5. Click on Apply to save.

Any movement on the red areas or boxes will be picked up.

Fix 2: Relocate the cameras or adjust the camera's neck to point away from these heat sources. 

The ideal position of the camera is 7-8 feet high, pointing downwards at an angle to cover the area where people will be walking across the camera’s path, and pointing the lens away from direct sunlight.