We routinely suggest checking battery cabling and connections for tightness, but often times the 120/240v wiring connections go unchecked until something goes wrong. I was in telephone contact with the owner of this Vantare regarding his situation at the time he noticed it, and sure enough, loose connections were found. Preventative measures such as checking the tightness of ALL electrical connections in a coach can be very time-consuming depending on the converter's approach, but should at least be considered annually. Heating up and cooling down, dissimilar metals with different thermal expansion coefficients, cause loose connections over time. Loose connections, just as Jon mentioned, cause resistance, and consequently heating.
I noted a similar situation in a Marathon at the POGX rally in Austin. That particular situation was only apparent by the loss of one AC "leg" of shore power in the coach.
Ben Cummings
U.S.A. Luxury Coaches, LLC
Clearwater, FL