I was wondering how much lateral movement is typical in your rear rack?

I have a cheapo PlanetBike Eco Rack. One bracket goes to my seat stay mount, the brake is in the way of the other so it is hooked up to the brake bolt.

I notice that when I am pedaling hard, or when I move around the rack with my hand there is more lateral movement than I'd like. Is this normal considering how I have it installed/for this rack, or is it supposed to be more rigid? The rear of the rack moves about 1/4-1/2 and inch if I jiggle it around.