quantities are making the price per 100g wrong

the price per 100g is wrong when a product has quantity ( eg. x2). It seems it is because is doing 227g *2 it's adding more than it really is. it's 0.66 instead of the reported 0.33. example: https://www.trolley.co.uk/product/linda-mccartneys-2-vegetarian-mozzarella-1-4-lb-burgers/JAR685?q=Burgers&p=26