So again 823A v3.1.0.956_22041511

I too have issues when someone is close/under the camera, at the point tracking is intermittent and laggy.

I suspect the system expects people to be rectangles taller than they are wide, once under the camera then the moving part of the image may not fit the cameras idea of what a person looks like.

My advice as soon as you have movement the the lower third of the picture and not above ( exclusions aside) pan down, even if you don't 'recognise' the object.

Other than that great camera, look forward to futher firmware upgrades, improving this in future.