Odds of it being the converter are ZERO
Odds of it being an open neutral on the park side of things EVEN IF YOU HAVE a 30 amp RIG,, Very very high;
Imagine a water system We have a tank, 3 fittings on the tank
From one fitting we have a pump, this pump sucks water out of the tank and powers some water powered stuff,, Water then goes to a "T" fitting.
On the other side of the tank is a pump that sucks water from that "T" fitting and after pulling it through some water powered stuff retusns it to the tank.
And connectd to the 3rd port on the "T" fitting is a line back to the tank that can water either way depending on which is using more water just now.
Now imagine one side is using very little water,, and that "Neutral line" gets blocked.. The other side is still pushing water in so the pressure goes higher and higher till something goes POP.
Electricity sorks the same say.. IF the neutral goes open then whichever leg is using less electricity the voltage goes very high and till damage is done.
IF you are on a 50 amp RV both legs are delivered to you
On a 30 amp Rig you get one leg and a nighbor gets the other (neighbor can be on the other side of the park, or next site over) if the neutral opens somewhere underground (happened in one park I visit) then voltages go high/low depending on which leg is using more power at the moment.
(OH,, In the park where it happned they closed affected sites,, Ran new Very much better cables.. And a long-term renter drove a piece of Re-bar through one of the new cables,,, and a new sewer line, and... Well.... Let's just say he was not the manager's favorite camper :) .