It's a very small MW, people don't normally use those in sticks and bricks. Maybe power output is too low if it runs water. Should be steam only, and most of it should be dripping from the cover (with few tiny holes) down into the bowl with meal. Poor ventilation in the camper, need more fans maybe.
Living off store-bought frozen meals will get you an ulcer, will drain your batteries and your wallet too. A pot of cooked meat or poultry can sit at 40F for at least 3-4 days, just reheat it. Cooked rice - 5 days or longer. Reheating these things can be done without a MW, though the convenience is hard to beat.