Possibly because of how the question list is set up. Before, the questions were limited to something like a maximum of twenty a page with numerous pages that you could flip through, such a set up made it easier to return to where you left off since a single page is easy to be stored and recalled. Now with it being an "infinite" list that loads up more and more as you scroll further and further, it seems that is harder to maintain the position on. One thing you can try is to open up a question in another tab, rather than the same one as the question list; this way allows you to close the tab with the question when you are done with it, and go back to the tab with the question list which should be right where you left off.
Personal experience with both versions and using the tab way, as well as my thoughts and theories about the changes.