DC1601B Demo board input line caught fire during use
The problem is probably inrush current, and DC to DC converters can source a lot of current. On startup it could pull the upstream power supply down and that would cause it to source even more current. (like if the sourcing supply was lower than 12V, then the boost feature would kick in).
I've had DC DC converters burn up their inputs before, usually it was a transient, the electronics got pulled low briefly which caused the DC DC converter to source even more current. Too much current was pulled through copper and things burn up.
The way to avoid this is with soft starts and current limits (which should be used especially when DC DC converters are connected downstream from each other). The DC1601 has a current limit and a soft start, which should be used every time as the manual suggests.
Its also possible that the crimp could have played a role in this, as extra resistance can expend a lot of power. (10mΩ @ 20A would be 4W, 100mΩ would be 40W. 40W is a problem)