Comments added to a picture in an album that is private, requiring membership in specified group to be able to view. The comments appear in the New Comments feed.
A user that is not logged in is able to view the comments for the private picture, but the thumbnail for the private picture is not displayed. Clicking on that picture causes and error page ("Dang, something went wrong") to be displayed.
A user that was logged in previously attempts to do the exact same steps. This user thought they were logged in (I didn't see their screen for myself, so I can't confirm). Same problem. The go back to the main screen, login, and then are able to view the picture. Suspect possible stale session for this user.
Either way, this scenario should be handled more gracefully.