There is a possibility that the EMS is "Off" somehow.. Low posibility but still there. Compare readings on the EMS display when another voltmeter.
You said the park had LOW voltage issues.. but they took care of that. now you have HIGH voltage issues.....
Here is how that happened.. The campground's wiring is what I call Anemic, it's not up to carrying the full load of the campers there.. THUS the voltage loss in teh wires causes LOW VOLTAGE when you load it down.
THe park applied to the power company for a higher voltage "Tap" on the transformer.. This means that now under load you get the proper voltage. but when the load goes down your voltage is too HIGH.. It is still the park's fault but to catch it you need a recording voltmeter.. Something the power company can provide. but they may charge.