"Many things are important, Melkor; that was a very trite question. And Hephaestus, do try and keep up. Your assumptions in that area are simply wrong. But I do not intend to give away any of my military plans, else what sort of general would I be? All that is important is that I do not think there is any threat. So that is that."
Absolutely. Against one of his base principles.
He keeps telling you it doesn't matter, because it really doesn't. You are not going to affect his strategic thinking, so even if by some random chance he was wrong, it doesn't make any difference. He believes what he believes and he doesn't care what you think.
As it happens he IS right. Being perfect and all.