I suspect that the high temperature is caused by a high amount of power being dissipated by several components. Since the component producing the most amount of heat will likely be the component with the highest temperature, you might be able to safely determine where this unexpected heat is being generated with thermal imaging. You may find a bad terminal crimp somewhere or a cross-threaded bolt that is not connecting conductors properly. You might even find out that your design of using the minimum gauge wires and buss bars that this presumed 65° C temperature rise is normal.