Guild Wars 2

For the living story, I noticed that there seems to be only 2 dirt covered objects out of all the possible locations of the map in Diessa Plateau.

I know that the last of the items have been released for this “scavenger hunt” but after combing the map’s possible locations for an hour I couldn’t find the last item (logbook).

Are there only 2 possible dirt covered objects per map?

3 in Diessa Plateau
3 in Wayfarer’s Foothills

Dulfy’s guide has the possible locations if you want more clues