Hi,
I came back to the game last week, and when I open my sightseeing log, it only shows an empty 5x5 grid, without any of the "clues" nor any of the vistas I had already unlocked.
It also shows 0/0 at the bottom of the window.
I went back to talk to the NPC in Gridania in case I needed to have the logs "unlocked" again, but she speaks to me like she did the last time, as if I had unlocked it and was ready to explore the world to find it.