Apologies I wasn't clear; if you look at the RHS of the diagram, you see Headset L and Headset R (pins 3 and 4) go into a 2 core shielded wire, with the shield floating on the LEMO side. However, the diagram calls for a shield drain wire to be created on the LEMO side, and run along the length of the wire and terminated to the back shell on the GMA unit. This is in addition to the shield of the 2 core wire having a shield drain onto the GMA back shell.
What looks like a duplication is that the 2 core shielded wire is shield terminated twice; once by running a (normal unshielded) wire outside the 2 core shielded wire and terminating it onto the GMA, and another by terminating the actual shield onto the GMA.