I'm just shaking my head at such an astoundingly stupid design decision. It's a friggin' high-current conductor path, whether it's used that way or not! Even if the two bars had been bolted in direct contact, as any barely competent designer would have made sure to do, that connection would get warm carrying 100A. Bolting thru the plastic sheet, which looks like ABS which deforms at only 160ºF, leaves the bolt, a relatively poor conductor, carrying all the current there, ensuring it would get even hotter and at least deform the plastic, further loosening and lightening the bolt contact, with a snowballing effect of worsening conductivity making more and more heat until the plastic has melted and the whole juncture is the rattling, sparking, burning mess Will revealed to the world. On top of that, using AP-store insulated crimp eyelets on the ground side busbar? You gotta be kidding! Astronomical incompetence!!
And then with the typical corporate ass-covering in an attempt to avoid the comprehensive recall order they should have issued immediately, they deserve to go under. Any company that would allow such negligent design where such hazards lurk should cease to exist.