It bothered me enough when I was about to buy this, that I sat and mocked it up in illustrator. That’s when I realise that the two arcs are indeed concentric.
Also the middle of the corner is thinner than the rest, because they aren’t actually circles but squircles. They could’ve done some optical correction, but that would probably complicate the manufacturing.
Also, see how the dock aligns perfectly with the screen corners to get over it :]