It is a strange anime, as first it was a book (text only, no illustrations except the cover) then it become a manga, then anime. And the scriptwriters for the anime took some peculiar decisions about flow of time. At the end of each chapter, the next chapter is announced by the protagonists, but one of them uses chronology order and other uses broadcast order. Then in the second release, they went for chronology (or so I have read) but got a time loop of eight similar chapters. The longest running time loop in TV series, perhaps?