If it is the Suburban SW6DE the water temperature is not adjustable. It is a fixed 130F. The high limit cut out is fixed at 180F and relief valve will open at 210F or 150 psi. It is likely the pressure build up during heating of the water is what is causing weeping of the valve, but it would happen regardless of fuel source. See attached.
Most RV water heaters have a fixed thermostat ( Not adjustable)
The temperature is set at the factory probably for safety reasons
The OTP relief valve on our 6 gallon water will sometimes expel water on startup. Also small pieces of debris or scale sometimes get stuck in the OTP's valve seat causing it to drip constantly
Never considered it a major problem unless it was continually dripping water .
Trailer: 2013 Escape 21 Classic Number 6, pulled by 2018 Toyota Highlander
With the water heater off and no HOT water in the tank and the hot water tank full of cold water you can flip the lever on the pressure relief valve so it sticks straight out and bleed some water past the sealing face and most times flush away a little piece of calcium or slag of some sort to clean up the faces. We always called it "exercising the valve". Then. Reseat it by flipping the lever back down. Heat the water and hopefully it will quit leaking. If not you can buy a new valve and install it. They do spit a little water at heat up times now and again as was posted too.
Strike while the iron is hot. Live every day as if it were your last and one day you will be right.