Yes, when using OnCompassChanged, you need to disable Rotate Camera By Compass.
When multiple scripts control the camera at the same time, they will conflict and you can get any unpredictable result.

do i have to disenable  "Rotate Camera By Compass"  if i use OnCompassChanged()
i need some explanation about when using that please .
cause some times when I use it while driving it start in correct position and degree but suddenly when I go on a curve it start to be Wrong "Degree"