One of the most-downloaded SAB apps is a Study Bible by Grace Ministries, India, with extended footnotes. These notes often have embedded cross-references in them [which are wonderful - as the user can follow the trail and read the supporting scripture passages]. When they click on the back button, you come back to the previous/original note that you were reading [which is also great] BUT the note scrolls back to the top, and so they have to scroll down through the note again to find where they were up to and continue reading from there.
So, I’m suggesting that it would be far better (and a lot less annoying) if the app returned the user to the previous note IN THE SAME vertical POSITION.