Happens to me on the mobile web version on Chrome. The feed doesn't reset while I'm on it, but it will if I go to a thread and hit the back button. Not only does it refresh, but also sometimes reorders the feed (because just keeping things chronological makes too much sense,I guess), so it's literally impossible to get back to where I was.
My suggestion is to just get use to it, because Facebook has made it obvious in the past they don't care about user feedback when it comes to the news feed.