I have two C425 cameras.  Occasonally they will begin announcing over their built-in speaker "SD Card not formatted Please format SD Card" (or something similar).  When I check the app everything seems to be working.  It seems a motion event will trigger the voice message.  I have to reboot the camera to stop the voice message.  

Regardless of what the problem is, It seems that the voice message should not be announced and instead it should be an in-app notification if there is a problem with the SD Card.  Or we should have the option in the camera settings to turn off these messages.  Having the camera verbally announce to the world that it's having a problem would give bad actors the impression that they are offline.