Wow! Unplugged 50 to 30 amp adapter....50amp female melted

The hardware is simply crap. I have seen (and have in my storage bay) 30 to 50 adapters that are burnt and melted despite not having used more amps than necessary (proven by the fact that the 30 amp breaker never tripped). No matter, when I disconnected from shore power I found a hot, scorched , melted and mis-formed 30 amp plug. I don't pay it much attention and use it at the next site as well. I buy a new one from time to time but I don't get it much consideration on a daily basis.