When braking get a diving board sound
 

I've had my 2011 Santa Fe for two years now and when I brake sometimes, but always when I take a downward sloping turn (especially out of parking lots), I get a sound like a diving board. I've started to joke that "another gopher jumped off the diving board", but it is disconcerting not to mention it makes people think, including myself, that there's something wrong with the car.

Anyone else experience this? What is the issue?