Note: please make sure to update the camera's firmware to the newest version.
IR-cut filter is a mechanical shutter design that blocks or delivers the IR – providing a high-quality image with true color reproduction – irrespective of day or night. And the clicking sound comes when this component switches the mode based on the light analysis. Especially when the light changes at dusk or dawn, the clicking happens more often as the light changes quickly and obviously.
Here are some suggestions to avoid the clicking sound:
To avoid the camera facing reflective objects, like glass, windows, silver metal, ceramic tile, etc. The camera will keep detecting the light and making clicking noises.
Avoid objects or human bodies that are too close to the camera.
Prevent the camera from capturing a big range of white objects, like walls, white beds
Avoid strong light illuminating the camera frontally, such as indoor lights or reflection.