I recently have started getting multiple appearances of my shared drive(s) on the desktop. I recently updated Server and OS X ML. All I know for sure is that when writing from most apps to a file on the client machine of the shared partition, I get a another appearance of the drive icon whenever writing to the drive. They just keep on accumulating.
My workaround for now it to open up Finder prefs and uncheck the box, "Connected Servers." Then, re check it and viola! The secondary appearances go away, only to return the next time I write to a file on the drive. And so it goes... Of my three clients I only see this in one of them.
Here an example:
Mac Pro, OS X Mountain Lion, (3,1) 10GB RAM, 500GB HD+250GB SSD