Any refrigerator that vents through the wall rather than the roof is at a serious disadvantage.
Do some research on refrigerator baffles. Most camper manufacturers do a terrible job of installation. If the space is too large the air circulates around the cooling fins rather than through them.
Also do an LPG pressure test. My refrigerator was acting up and I discovered that I only had 9" WC in the system. I adjusted the regulator to provide the correct 11" WC and now the refrigerator operates much better.