I have had 8 C211s in my home for about a year now. 2 of them have started chirping (NOT the alarm) every time someone walks by them. It is a single chirp and only happens when someone approaches the camera. None of the others do this, and they all have exaclty the same settings. I have unplugged them, rebooted them, etc. Alarms are toggled off, and it doesn't matter if any/all notifications are toggled on or off. It is extremely annoying.