Update: I've updated iOS and all apps. I've also uninstalled many games and other free apps. After all this, I'm still getting the "Open this page app store" pop up.
Today I had a breakthrough, it eventually stops if you keep reloading the page and I noticed it almost exclusively happens with one particular banner ad: "Download the free Twitter app". If you keep reloading the search page, you'll eventually get served up a different banner ad than the "twitter app" one. It you get the "download the free twitter app" banner ad, it is almost instantaneously triggers the "Open this page in "App Store"?"
Maybe not the smoking gun, but a clue...
Today I had a breakthrough, it eventually stops if you keep reloading the page and I noticed it almost exclusively happens with one particular banner ad: "Download the free Twitter app". If you keep reloading the search page, you'll eventually get served up a different banner ad than the "twitter app" one. It you get the "download the free twitter app" banner ad, it is almost instantaneously triggers the "Open this page in "App Store"?"
Maybe not the smoking gun, but a clue...