My guess is that the modified firmware will build a model of the contactor's temperature; a fancy way of saying they make an informed guess. When the guessed temperature gets too high, then they limit max current (either discharge or charge current) and pop up a message saying that due to an over-temperature situation, maximum power is temporarily reduced.
So then you can still do a few "wide-open pedal" runs to impress your friends, just not all day. As long as the model is reasonably accurate, it should prevent excessive contactor wear. No doubt in the fine print for the 500A contactor (a wild guess) will be that this is subject to a "typical" duty cycle. Hot footed drivers can exceed this duty cycle without realising it. So it's not really incompetence on the part of the original designers, more a lack of foresight. It's hard to foresee every co-ordinate a design space will hit in real life.
Sure, a really experienced designer would have thought "wait, I bet there will be some more fine print on this" and gone looking.