The party line is that it's a printing error. But really, how often does Marvel publish something with the wrong copyright information? Pretty much never would be my guess. I mean, c'mon, isn't that one of the reasons companies keep their legions of lawyers around?
And if it was a mistake, Quesada's top dog. Ultimately, it's all his responsibility. The buck stops with him. To allow the copyright information to come out wrong on a product where you know its of utmost importance that you don't, where you know screwing up might mean losing the chance for one of the greatest writers in the medium to work for your company... well, it is pretty moronic.