After driving our Acadia on the highway for an extended trip I've noticed that the front air dam warps in the center, in other words it has a big dip in it. It seems like it does return back to the original position after a couple of days. The dealer has replaced it once, but we just returned from a weekend trip and noticed that the center of the new one is also bent in the center. Has anyone else had this problem? I'm refering to the lower 3" piece of plastic on the bottom of the front bumper.