My guess is that it is almost from the process of making the paper. I see this is as well, but you have to try so hard. Any glossy surface will reflect these imperfections at only a very specific angle. I think it looks like it comes from the roller marks or something like that. In the second image, I almost don't see the problem. I would imagine the only thing you could do is buy another batch or switch papers. In my humble opinion, I would consider this minor, but of course its the end customer whose opinion matters most!
