What Version are you using?
Have never seen that behavior. I use middle mouse button for rotating and right mouse button for panning. But it also works in your combination with Ctrl.
Usually the center of rotation (COR) is set to where the mouse pointer was when you entered the rotation mode, or if there was a drawing object nearby it will snap to that one.
Check in the Support Tab -> Options what you've set for the COR behavior.

If unsure what the options mean press F1 once your are in that window.