Ring Doorbell wired - Missing motion detect event

I just bought one ring doorbell wired. Tonight, the doorbell captured my neighour towarded to our home but then stopped and standed in the middle of the way. I got alert for the motion and then turned on to the live view, I saw he standed there for a while then turned back to his home. The recorded video is only around 30 seconds, and contains his towarding to our home and standing there, but did not capture his leaving. Could anyone help to explain what maybe wrong? I thought leave is also a motion that should be detected and recorded as well. Thanks