I just upgraded to OS X Mavericks. I'm using a July 2011 Macbook Air. Now all of a sudden, when I'm typing, the volume randomly goes up and down, along with the pop up icon appearing that looks like i hit F10, F11 or F12. Which I am not. The key that triggers this behaviour randomly changes, so i can't even try to "type around" the offending character, as if that was even an option.
PLEASE, someone tell me that you've confronted this issue as well? It's only been a few hours and i'm being driven absolutely crazy!