I'm wondering if it was glue residue, wouldn't it be noticable on the other side too? Is it possible that it's a slight crease along the card? The way it's catching the light suggests to me a card that isn't totally 100% flat. Having said this, we only have these pictures to go by, the first one there being completely useless because of how blurry it is. Being the buyer, if you receive it and it's not as described, I think you're covered by Ebay policies, yes? I hope it turns out its just a camera glare keep us in the loop!