Pursuant to that whole off-camera returning-the-stones thing is an interesting twist that the directors have clarified: that the ending we saw with Cap returning as Old Cap involved him returning the stones and then going to live with Peggy Carter in a different timeline, not the Prime timeline that the stone-returning takes place in, because that would have resulted in a branched timeline. And that there may be a whole story there that they plan on telling that involves Bucky’s knowledge of the two Captain America timelines and how alternate-timeline Cap was able to come back to the Prime timeline with his shield (and apparently without Mjolnir?)
