This is almost certainly the ads that they're talking about in this post. They don't really have any control over what kind of trackers are included in 3rd party ads. I would wager that if you reload the site at different times of the day, you'll get different numbers.
It's a sad reality of the advertising world—the people building the ads simply don't care, and the ad networks can't (or won't) do good QA.
It's a lot more complicated than that. Yes there are lots of ad networks that are crappy and don't have good QA but lots of this is down to the buyers themselves.
The big clients and agencies who do ad buys have thousands of requirements including 3rd party verification, tracking, conversion pixels, etc.
We run one of the fastest ad networks available with everything optimized to the fewest network requests, yet a single campaign from someone like ATT will mean a dozen other tags that needed to be loaded if we run their ads.
It's a lack of trust, standards and actually technical understanding that's hurting this industry the most.
It's a sad reality of the advertising world—the people building the ads simply don't care, and the ad networks can't (or won't) do good QA.