I found the solution on the apple forum:
Take all Batteries Out.
Roll up a small piece of Tin Foil about the size of a Pea.
Drop the Tin Foil Ball down the Battery Compartment.
Put your Batteries Back In.
You should have a Working Keyboard.
This worked for several people on here including me.
I'm still running 2 months later with my rolled up piece of Tin Foil in my Battery Compartment.
I know it sounds Crazy. That's what I first thought.
Apparently Apple did not make the + Terminal Inside the Keyboard correctly.
Try it. What have you got to lose?