IMO a properly working regulator should never block the flow.
You would perceive a difference in flow when the outside pressure is too high.
As info, the hose connector on your RV has a one way valve in it to stop flow going out of the RV. About a year ago the spring in my valve broke. Resulted in intermittent water flow into the RV. The flow would at times cause the broken valve to close in the wrong direction. After I figured out the problem the only 'on the road' fix I could come up with was to just drill a hole through the valve till it could be replaced.
1984-2014, 1984 Hi-Lo Fun Chaser 21', 1972 C-20
2001-2013, 1995 Airstream Excella 34', 2001 F250
2013- Now, 2006 Itasca Meridian 36G, 2014 Jeep GC