I always ( when 50 amp is available) use the 50/30 adapter. chances are the 30 amp plug got hot and started burning ever so slightly and then got worse. The most power you can pull is 30 amps because the main in the camper is 30 amps. If plugged into a 100 amp plug the most current you can pull is 30 amps so there is no danger of overloading the supply cord. In the event of a short the 50 amp breaker would trip faster than you can blink. # 14 copper is considered a 100 amp fuse link so it would get darn hot and you could maybe start a fire, but you will never overload a #10 cord because of the inside main of 30 amps. I carry a replacement plug in case mine gets damaged. Too many pedestal outlets are burnt which just compounds the problem
