I bought these about a month back as a pair I could use for work/running from a guy on Kijiji (he bought them custom from O). I didn't notice this at first (perhaps because it has happened recently), but when they are sitting on a flat surface one arm is higher than the other, I'm not entirely sure if one is bent up or the other is down, which causes it to sit slightly angled on my face - a real piss off now that I've noticed it. So just a couple questions, how exactly could this have happened? Is it common? And most importantly, how can I correct it? Any help is great, thanks in advance.