Good question. And I'll join you here with what I think might be similar issue. I have DS-7608NI-I2 nvr (which manual says it supports human vehicle detection) and DS-2CD2187G2H-LISU camera. I setup nvr to use line crossing detection with both checkmarks for human and vehicle. Yet on my hikconnect app I always get "line crossing detection" notifications that are generated due to shadows and lights, basically none of them are for "human and vehicle" recognition. Am I doing something wrong?