...Today Apple released a keyboard update for both the MacBook and the MacBook Pro notebooks. In regular Apple style, their release notes are not extremely profuse, 'This MacBook and MacBook Pro firmware update addresses an issue where the first key press may be ignored if the computer has been sitting idle. It also addresses some other issues....Periodically, when I wake my sleeping MacBook, it accepts a single keystroke in the login pw dialog then stops responding. I close the lid to put it back to sleep, open it, and all is fine.
I'll see if this fix makes this problem go away.