In 2011 Legacy with CVT, the cruise control maintains speed downhill only about 10% of the time. Otherwise, it remains on, but vehicle accelerates downhill. This did not occur with my prior 2005 Outback, or my wife's 2013 Impreza. Dealer claims downhill acceleration to be normal. Since I live in a mountainous area, cruise control requires constant monitoring, cancellation and re-set. Any one else with this problem? I had no such problem with prior Accord and Odyssey.