I've had an issue for the first time yesterday with a 1-year old T8. Was cruising for a a tad less than a couple of hours at 80m/h for about 150 miles. I fully refuelled the tank when leaving and ended up with an empty tank. Had to refill 13 gallons. Was driving on pilot assist with no air conditioning and no outside addins (caravan, roof racks or whatsoever). I was pretty surprised to have such consumption. I checked underneath the tank and did not see any leakage at all. Would any of you have any idea how this happened?