I agree there could be a further problem with the OP's rig, but I don't understand why this one should be singled out. Any ungrounded modern RV will have a "hot" chassis when not properly grounded, unless it has an independent earth ground. There's no more probability of this one having a further problem than your own or mine having a problem. In fact, I'd be suspicious of an ungrounded rig that doesn't have a "hot" skin. That could indicate a neutral-ground bond, and if plugged into a reversed polarity source it would be a hard-core life-threatening hazard.