I know exactly what you are talking about. I've seen it a dozen times or more. I don't know exact manufacturing process, but speculate only. I do think perhaps as they are running out of the metal oxides that get vacuum coated to a lens this can happen. I do picture the process being as you say "sprayed" on and perhaps that's why the edges are the only area this seems to affect. Don't worry. It shouldn't turn into a warranty issue , but if it does send them back