Also, I haven't been very active in the game, but I figure a changeling wouldn't want to draw too much attention to himself. Right now, he suspects that one of Silkur's rivals might have cast some kind of enchantment on the town, but he will not risk bringing this up with the captain around.
Whether his methods were magical or mundane, though, the main thing is that Tiv sees a powerful mastermind in the shadows. As someone disguising his true nature, he is paranoid wary of deception, but he may become more open if he sees Dusk walking around without hassle.