Since the last update (18.104.22.168) the flow view option is now missing in the published specification. I still have the icon on those specs I published before the update. On anything published since the update, on the Grid view, the option icons are no longer present.
Also, I can no longer see the Specification view, only the prototype view. My developers can't access it either. The options to switch between the two is also missing since the last update. I haven't changed any settings when I'm publishing either.