@hokpe I'm having exactly the same problem.. I bumbed up the sensitivity and still nothing. I also thought it could work in pair with the Tapo T100 motion senso, but they haven't introduced this feature yet. Im using the 1.3.10 firmware. 

  @hokpe well although my 2 C425 work better, the issues are still not resolved. although you fix a trigger range area, the cam might still trigger movement far outside the area.

also 1 constantly gets firmware updates and the other only far far later if at all... 

sensitivity is an issue, person detection and movement is an issue... sometimes (the 2 are concerned) frame the movements person pet whatsoever, sometimes not...

all in all the software / firmware is not very good.