I just bought a few pairs of Adistar comps and the first pair has some strange wear after only 150 miles. These were on closeout and are likley 2-3 years old. When viewing the shoes from the back the top of the left heel is approximatly 2-3 mm lower than the top of the right heel. It's like the heel has sunk in. I did not notice this when I started to wear them and my second pair does not have this issue. Could this be related to the shelf age of the shoes? Is this a normal sign of wear? I'd like to get several more pairs but if they are doomed out of the box due to their shelf age I'll think twice. Thanks!