returning from locked screen (saver) sometimes lies about focus

[kaduk]

About half the time tonight, when returning from screen saver (locked screen), I see that my terminal window is highlighted as being the active window, and start typing into it, only to see no response.
Clicking in the window, or doing a couple of alt-tab sequences to return focus to it, restores normal behavior.
Admittedly, this is probably not a debathena bug, but I have no idea where the proper upstream is, and little time right now to search for it.