Without more information, this is sheer conjecture, however I know of one very recent model Ford pickup that the operator shall we say oopsed by coming straight across a ditch instead of angled, got high centered and the cat converter (which runs *very* hot and they keep adding *MORE* of them!!!!) lit the grass on fire. From there, Ford in their infinite wisdom used plastic fuel lines... which melted... thank goodness the fuel pump shut off when the motor quit due to fuel starvation. It was rebuilt, but wow, what a mess. This isn't the first issue like that we've seen, but the most recent that comes to mind.
So it's not all that uncommon, but not all that common either. More or less, sitting in a great fuel source (dry grass etc.) with the engine running or sometimes just shutdown has done it.
That said, perhaps there is a design issue involved (plastic fuel lines?? something in proximity to a heat source that is more of a problem offroad where testing may not have been as thorough??), I haven't examined one of these beasts all that closely to avoid the desire to get one so my family can go out in one vehicle, not two.