People only mode not working

Still getting motion notifications despite people only mode being on. The doorbell is correctly detecting people i.e. notifications display Person Detected when it’s a person. But I still get random Motion Detected notifications that are just cars. I have tried: toggling people only mode on/off. Reducing the sensitivity. Turning off motion alerts (I get neither notification doing this). And tried adjusting motion zones - even disabling all but one zone which is only facing a small nook I get notified about motion in other zones. Please advise