[jsb5717]

Sounds to me like the surge protector is faulty. If the issues exist while using it and all returns to normal when not, then that should be a pretty good indicator. It must have some kind of internal short to allow 245v in the coach.

An RV 50a shore power outlet will have two separate legs of 120v. Those 2 legs of power go into your RV breaker box on 2 separate 120v feeds. Everything in the coach runs on 120v...NEVER 240v. If the short power outlet is correctly wired then a short is allowing a cross-feed of current. It could be your cable, but it sounds like your surge protector.

Ideally you would install a quality EMS system.