So I'm new to long boarding. I just bought a Robert August II board by Surf One, shipped from skateone. I just noticed today, after having it for two days, that the board is twisted a little bit toward the bottom. It's not totally flat like it's supposed to be. Is that normal for longboards? Is it normal for just flat longboards? Is because of something I did? I haven't even ridden it that much. I'm just wanting to know whether it's "defective" or not. Thanks!