In the last few days, I've noticed that Finnish has reset itself in some way a few times. About ten minutes ago, I couldn't go to the My Lessons page without opening a library lesson first (instead, it was taking me to the "Choose your first lesson page"). Not sure if you're aware of this issue.
I've got a feeling the problem might be the following.
I imported a handful of articles today (maybe five or so), studied them and then deleted them. This means there are no "recent" lessons to show on the "My Lessons" page (normally it shows five). Therefore it must think no lessons have ever been studied and, consequently, it forces me to take a library lesson or import a new one.