Comment 38 for bug 556255

This same thing happens to me, but worse - normally upon returning from the second password prompt to the desktop, I am without keyboard input. The way I solve it is by choosing System > Preferences > Keyboard > Layouts, and then toggling the keyboard layout over to 104-key PC and then back to 105-Key (Intl) PC. After doing this, things are back to normal for the time being. Needless to say, this is quite a dance to do nearly every morning when I unlock my screensaver. I can't say that it (the double lock prompt) happens every time, but it happens more often than not, and the keyboard dropping out happens about 50% of those times.