Haven't followed this forum, so this may have been reported previously.
I am not quite half-way through LA-151, but every session is marked completed. Checked LA-161—which I had never visited—and it also is marked completed. NT-221 is also marked completed when I have only viewed the course introduction. A few other new courses are not yet marked completed.
All this makes the feature worse than useless, as there is also no way to uncheck the false check marks.