Well I put a call in to Madstad and was advised that sometimes the shield edge is cut sharp and the edge is not rounded enough.
Soo I pulled out a roll of electrical tape and ran across the leading edge and went for a ride. Sure enough NO WHISTLE.
I did reach up over the shield and remove the tape at about 50 mph (not advisable) but wasn't able to pull it off slowly to see when the whistle would come back. So if you have a whistle this test may be worth a try for you...