I've been a little absent from GA recently, but this is a new thing for me to see. Are advertisements supposed to be within the story body itself, when reading? I've always seen them either on the sides of a browser, one of the ones that peek from the bottom of the window, between areas (story body -> comment section), but this one was very jumpscare-y and makes reading a little silly.
This occurred on a Microsoft Edge browser, Windows 11. It happens at times. This page is my "Retail Ninja" story chapter 1, but when I backed up on the browser then re-entered the page, it was normal. Moved onto chapter 2 of same story, ads returned between paragraphs.