I scrolled down the list of articles, clicked on one to read it, and then clicked the “back” button and I am still at the same point in the article list (about 1/2 way down). I am on iOS 8.4.1 and use the “Comments” tab on FR. Maybe I am not set-up the same as you on FR? (I am set to “50 articles per thread” & “100 threads per page”...use “Account/My Prefs” on FR to set).
I just upgraded to 8.4.1 and am having the same problem. Hitting the back button goes to the top of the (latest) articles page. Argh....