I've noticed recently that my 7,8 F6, F7 keys seem to be higher than the other keys around them. Not much, but enough for a critical eye to notice. My PB sits evenly on a flat surface, so I don't think the case is warping. I'm wondering if this is something I just didn't notice before.... Or could it be warping as I use it. I always place it on a table when it's powered up. I haven't carried it in a backpack. I store it in a sleeve.