I've seen some posts that say even engines from Japan have the issue. So really debris is everywhere these days. Honda has it, Kia has it, now Toyota has it. Rule 1 never blame the design, or engineering.
Oh and that is my favorite video, he shows absolutely nothing, just a short block with heat damage like you say.
Due to the warranty pay they get for all that I just bet none of the removed parts get cleaned.
I like the story's from some people that have had this done, talk about, it was a few days or weeks it happens again.