The cables coming out of the twist grip for my Nuvinci N380 went "sproing" the other day and I pedalled home frantically in low gear. This isn't the first time this has happened. On closer inspection the problem was pretty easy to fix—all that had happened was the cable had come out of the little slot where it connects to the "gear ring" on the hub:
The little silver clip thing has the transmission cable attached to the bottom right hand side of it; you clip it into the bottom-right slot on the "gear ring" and then click it down so the top part sits flush, levering the cable tight. Theoretically it should click into place—there are little nubs in the metal which click into the holes you can see in the black gear ring part. But the silver clip keeps "standing up" into the un-levered position and from there it's easily knocked off as it rubs against the chain guard, and I lose my transmission again.
Is this a known failure mode of these hubs? How do I fix it?