I have the same thing on mine, but I'm chalking it up to a design element allowing any extra heat to escape should I ever want to use it in clamshell mode. I could be wrong, but seeing as how I've seen the same thing on a few of them, I think they might mostly all be like that.
lol.
I think they just screwed up on the specs. There is no reason for it to bow like that.
I don't mind too much personally, but it is definitely not the best fit-and-finish out there.