Have you performed a propane system maintenance. On mine they tested the propane pressure, cleaned out the flue, cleaned the burner assembly, adjusted the flame, and all the other little things related to optimum performance. One thing they did tell me is most RV refrigerator's propane functions are often a bit out of whack due to no maintenance.
My refrigerator is an old Norcold 682 and it's cools great regardless of interior temp. When I had to pull the refrigerator to access the cabinet space on it's side, I realized the insulation around the refrigerator shouldn't even be considered insulation. So I added new insulation on the sides, the top and the bottom. I also had the chimney and add on fans redesigned to optimize the flow. Even if it's 100 degrees in the RV, the refrigerator will still cool to the mid 30's. Don't underestimate the loss through the sides, top and bottom of the refrigerator due to poor insulation.
