So I noticed it happened just now when I was on the reply page to a thread I'd just revived. Thing is, I hadn't typed anything in the box yet, I'd just scrolled down to see the previous post when the page suddenly jumped back up to the post box again.

I was also loading another page like Fallin said, and those were still loading according to the tab bars, so I did an experiment and managed to replicate the issue. But then I closed out of Chrome and opened just one window and did the same thing where I go to the reply page, didn't type anything in, and scrolled down to the last post. Page still jumped back up to the post box :/