That means his last 4.7 miles was covered in 39:46, or just under 8:30 pace. In real marathons that people actually run in their entirety, bonks like this do happen. However, it would be surprising given how steady his first 21.5 miles was, even speeding up between 15.3 and 21.5 miles. Of course, it would only really be surprising if he was actually running these races. Presumably what actually happened was he made some kind of miscalculation on his last bit of course-cutting, or was held up for some reason.
One thing that is remarkable to me about Meza is the sheer number of fake marathons he has run. There are a lot of them. It looks like he started in 2009 or so, and has often done 3 or 4 marathons per year. They all seem to be done in similar times (gradually speeding up during that time span), so presumably he cheated in all of them. A marathon entry fee is what, like $150-200 these days? I guess that's not a big deal to an MD. Still, I'm surprised boredom didn't set in after a while. It seems that it would get old, constantly checking out courses for timing mats and places to park and whatever else was involved. But I guess that's just me.