I am reading a tire review at http://www.bicyclerollingresistance.com/road-bike-reviews/schwalbe-lugano-2015 and it says
the Lugano had a gigantic height stroke. Most tires have this, but the Lugano was awful, you will probably notice it on the bike. This is a sign of low-quality control.
quality control seems to be low as the Lugano used for this test came with a severe height stroke. To keep the price low, they probably just don't bin the bad tires.
What is it? This tire is very low-scoring so I think it is bad.