I have my “All Stories” list set to oldest first, unread only.
Since joining the beta program, read stories now show up as well. If I read a batch, return to the home screen of feeds to see how many I have left, and then return to All Stories, those I have just read still show as well as the unread ones. I have to scroll down through tens or hundreds of stories to get to my unread ones.
Same if I choose a specific feed and Mark all as read, they still show within the main list of all stories.