I am willing to bet that Dash 14 Komatsus with K-21 will shut down to idle only when step 2 overheat is still present" is not entirely accurate, although it seems a valid observation, but step 1 overheats still slow the motor, just not enough to really notice (max RPM about 2300 RPM step 1 overheat cuts it back to 1700 or so, just making up the numbers, I didn't bother to look them up, but it is close). thing is, unless you have a long run, you might not ever get above 1700 rpm in usual operation enough to notice.
But the [real] point about self resetting limp home when the motor is cool is accurate.