I have 3 C501GW cameras installed using the overhang mount option (they are under a roof eave attached to soffit)

Motion tracking is enabled and under the PAN and Tilt settings and I have Viewpoint 1 set as the main position of the camera. 

I have found that over time, after about 10-20 motion tracking events, when the camera returns to its 'home' position there is drift in the position.  The default position is 1-2 degrees different to the original location.   So over time, this drift adds up and the default position is now different enough to be a problem as the detection areas are out of alignment. 

It mostly has a vertical alignment issue. The drift sees it moving downward.

I then manually adjust it and re-save the Viewpoint 1.

Is this a known issue and any fix or workaround that can be done? I dont what to have to reset the default position so often.