The brakes need adjustment is all. They are setup too loose. The Prodigy doesn't have an axle count setpoint. The b1, b2, and b3 are boost settings. When you are stopping, does the display show voltage going to the trailer brakes? If it does, the brakes are working. You probably just need to jack the camper up and adjust the adjuster screws.
You can't see it here but behind the magnet on the backer plate are a couple plastic plugs that can be removed to allow you to turn the adjuster. Tighten it up enough to cause a light drag on the drums spinning by hand.