The British Field Support option under HQ is not acting as it should. When this is selected it now acts as an ability, consumes manpower and fuel and does not add the Support Truck to the HQ construction queue. What happens is that it begins a 70 second cool down after which it will have the same function.
As per the How to Report bug guidance, I have tried this on multiple maps, difficulties, uninstalled and reinstalled the game with the same result.
I include a screenshot.