This is the second MacBook Air Early 2015 where the function keys on the keyboard stop working. When you press the buttons, you hear a 'dunk' sound indicating there's input. When I boot to a good known OS, the same thing. I have tried reseting various plist, replaced the top case, re-loaded OS, etc... Has anyone else encountered this? I'm still convinced its a software issue but I've tried everything I know.
