Even using addons to pin-point exactly where the books or notes (which are, for several times, very well hidden) are located sometimes they are not where they are supposed to be.
This could be, of course, because the lorebooks don't exist anymore or were renamed and the addon "database" is not updated.
For several locations, like the very, very, very old ones, is understandable, as the author will not play again, again and again just to mark the new coordinates or remove the outdated.
For example: Right now, I finished (again), Khenarthi's Roost, but this time looking thoroughly for these pesky little things while questing. But, for example, Where I'll be that should be found during the quest Moon-Sugar Medicament couldn't be found in any of the locations marked by the addon.
Or what about Ealcil Notes, Pages 1, 2 and 3 during The Tempest Unleashed quest. I couldn't find any of them and with the quest finished, I can't enter The Winding Tunnels anymore to do a third check.
That's different of, for example, Your Silver Fur, a note that was part of the Khenarthi's questline that, after completed, was thrown near the wayshrine.
Why these others can't be too? Is it so difficult to put a god***it condition in the quest code telling the game that if that lorebook can only be found while having it active (which is VERY annoying, btw), to drop a copy or move the object near the guy that rewards you after the quest is finished?
Also, as an additional suggestion, the Eidetic Memory "page" could describe where that lorebook was found, to help other completing it.
I am the very model of a scientist Salarian, I've studied species Turian, Asari, and Batarian.
I'm quite good at genetics (as a subset of biology) because I am an expert (which I know is a tautology).
My xenoscience studies range from urban to agrarian, I am the very model of a Scientist Salarian.