Same thing on my iPhone. I gave up trying to read the article because of it.
Even safaris built-in reader mode didn't work, it wouldn't look past the first section of the article.
I'm guessing they're playing games with the DOM using JavaScript or something like that. Doesn't really matter, it completely broke to usability of reading the article.
I sent them a comment about it, I hope they listen. I really dislike this new trend of websites implementing their own custom scrolling behavior. I've yet to see one that improved on the default behavior in iOS.
I fear it's a ploy to keep my eyeballs on the site for as long as possible. Not a fan of this at all.