When activating the third person view after entering an armoured vehicle in the Commander's position there is no crosshair visible*. Commander's view is moved by the rotation of the vehicle. After swapping to either the Gunner's or Driver's position then going back to the Commander's position the crosshair becomes visible. With the visible crosshair the Commander's view will remain where it is pointed irrespective of vehicle rotation.
*This only applies to armoured vehicles that do not have a weapon in the Commander's position.