OK, I think the trailer jack was off the scale on the second weighing. NO the only way to know your tongue weight is to put only the jack on the scale.
Yes, something is wrong as the WD takes weight from the tongue and shifts it to the front tires of the car and to the trailer tires. You either have the WD way to tight as you are taking too much weight off the rear of the car and putting it on the trailer and the front of the car or you have a tongue weight closer to 2000 lbs... not likely.