Unlock screen sends password to active session

I've observed a very odd behavior a couple of times now when unlocking the screen. Basically, the password gets entered into the unlock dialog and also goes to whatever the active application is. I've observed it happen once when I typed the wrong password, and once with the right password.

Since this isn't terribly clear, let me explain what happened. I was running a chat client and had an IM window up. I walked away from the computer for a few hours. I came back later and tried to unlock the screen. On the first attempt I entered a different password on accident (let's say I typed 'WrongPassword', followed by enter). On the second attempt, I realized my error and entered the correct password. I got in, but soon discovered that my first attempt went though to the IM window. So I ended up IM'ing 'WrongPassword' to a friend (luckily this was someone I trust). The timestamp on the IM lined up with the first login attempt.

The second time I observed this, it was on the first password attempt (I typed the right password this time). The difference here is that it only picked up the last few characters from my password, and the active application was a terminal window instead of an IM window.

I'm running Ubuntu 12.04 AMD64 and using GNOME3 (maybe that has something to do with it?). I talked to a coworker who had experianced a similar issue (also using GNOME3). I have a third system, also 12.04, AMD64 with GNOME 3 which has not had the issue (this particular machine gets locked and unlocked much more frequently).

Does anyone have any Ideas? I'd be happy to post hardware details if you think they are relavent.

Thanks!