Assume that you access a file or a folder over a third-party network on the offline share. In this situation, File Explorer displays Offline status as "Online" and Offline availability as "Not available" in the details pane.
To fix this issue, install the hotfix that's described in the Microsoft Knowledge Base article 3071345.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
See the terminology that Microsoft uses to describe software updates.
Windows Server 2012 R2 Datacenter, Windows Server 2012 R2 Standard, Windows Server 2012 R2 Essentials, Windows Server 2012 R2 Foundation, Windows 8.1 Enterprise, Windows 8.1 Pro, Windows 8.1, Windows RT 8.1