I think every car or truck I've owned has done this to some degree. The air vents are usually controlled by a door/valve which gets its control from engine vacuum, and also a spring to preload it in the closed position.
When you step on the gas the vacuum is temporarily lowered and a spring will close the door that sends the air to the upper air vents. Usually there's a vacuum canister somewhere under the hood that stores vacuum and prevents this from happening. However sometimes that's not enough, or sometimes there's a broken hose or cracked canister.
I haven't had my Expedition long enough to find the canister yet. Maybe someone else will also reply with better info.