Bang and Olufsen 3i headphone repair

These B&O headphones stopped working with the iPhone 6 Plus (no audio out), and were intermittently opening Voice Control or playing music on their own on an iPhone 5s. Here's what I learned while fixing them.

1) The iPhone 6 Plus seems to shut down the headphone audio if there's a problem with the mic/control circuit. The iPhone 5s copes, at least in the short term.

2) Others have reported similar odd behavior:

iPhone 6 iOS 8 Voice Control comes on randomly while using headphones, how do I disable??
 
I wonder if small interruptions of the common circuit can cause static that's basically inaudible to mobile users but the phone is recognizing them as command pulses. Or if the mic side opens, or shorts to common due to a bad cord, there's no audible signature unless the user is on a call.

3) The B&O 3i cord has five conductors that go to the four-circuit plug. They are:

Tip    -  Green - Left speaker
Ring  -  Red - Right speaker
Ring  -  Red/Green - spiral-wrapped shield for microphone, twisted together with
         -  Copper - common for the speakers.
Sleeve - White - Microphone center conductor

I used four layers of shrink tubing to reconstruct the plug housing. Here's photos of the wiring and rebuilt plug.