I don't know if you remember about that infamous iOS problem from a year or so ago. When peoples iPhones e-mails, AppStore, iTunes, music etc. just stopped working after an iOS update.
Yup, I remember that one. I've been trying to replicate it here, but can't. cnn.com does nothing unusual. I also tried the two wiebevdw has consistent problems with; ajax.netwerk.to and www.farjestadbk.se .
The first had a strange popup asking if it was okay to save cookies. Don't know why it would ask since the iPad is already set to accept cookies from sites I visit. I refused to touch the button to okay it and went on to the second site. As noted, it's a sports site. It did generate a popup over the main page, but it was clearly produced by the same site as the info was related to it. If you go in and out of the site, it produces various types of popups, but they're all being served up intentionally by that site. Nothing nefarious going on.
This is an older iPad 3, and while it runs 9.3.3, it doesn't support functions newer units do. I can't even install an ad blocker on it as they all require newer hardware than what I have.
No doubt it's beyond annoying for those having issues to the point of not being able to figure out how to stop it no matter what they do. Buy why to such an overall small percentage of iOS 9.3.3 users? What's common to those?