I am studying words from several lists, but never from more than one list at the same time. When I'm done for the day, I never leave a list under 'Adding Words From'.
Yet here I come to start my first Skritter session today, and under 'Adding Words From' I see Old Hsk1 and Hsk4. I really thought I had already finished both of them.
Now, I could be wrong about this, although the list with the dates suggests otherwise, but I can't be wrong about my absolute rule to not leave any lists where I found the two I mentioned just now.