The vehicle does have a "normal" heating system similar to a passenger car. It makes more sense to use that heating system instead of operating the GAS heating system while driving. 

To answer the question correctly, let's check the owners manual:

Operation while driving – Directive UN ECE R 122 stipulates that a safety shut-off device is required if motor homes and caravans are heated while driving. The Truma MonoControl CS gas pressure regulation system satisfies this requirement. Throughout Europe, a type-tested liquefied gas heating system may be used while driving (according to the directive UN ECE R 122) if the system includes a gas pressure regulator with an appropriately configured gas installation. National regulations and rules must be followed. – If no safety shut-off device (e.g. as contained within the Truma MonoControl CS gas pressure regulation system) has been installed, the gas cylinder must be closed when driving and information signs must be attached in the gas cylinder protection box and in the vicinity of the control panel. – Liquid gas equipment must not be used when refuelling, in multi-storey car parks, in garages or on ferries. – To prevent damage to the appliance from spray water, such as when cleaning the vehicle, do not spray water directly into the cowl.