There seems to be an incorrect check that is preventing Druid King Vestments Clue and Wispheart Totem clue from appearing properly only for certain characters in the Tomes of Tribute section of the Lore Library. This seems similar to the issue that was affecting console for a couple of weeks after Firesong's release, but I'm not sure whether it's exactly the same thing.
I'm experiencing this on PC-NA. I have Firesong from when ZOS gave it free to High Isle owners. I have had the Druid King deck unlocked (and upgraded with both clues) from within a week of Firesong's release. The same is also happening to multiple friends in the same situation.
Currently my main character has found and read both of these Druid King clues, and they properly show up as read under Tomes of Tribute for that character. That character has done all of the Galen storyline and all of the Tales of Tribute storyline.
On an alternate character who has been to Galen and who has unlocked (and done many of) the ToT dailies, but who has not done any of the Galen story quests and has not finished the ToT questline, neither clue appears even unread anywhere in the Lore Library. For that character, the Tomes of Tribute section says there are only 19 books total (3 Pelin clues, 2 clues for each of the other 7 base game decks, Seeking Tribute Players, and Torn Note from Brahgas), when it should say there are 21 (including the 2 Druid King clues). For that character, the Lore Library is acting as if I did not have Firesong at all, even when I'm logged onto that character and standing in the Galen zone playing Tales of Tribute with the Druid King deck fully upgraded with the clues in question.
It doesn't seem to be a check for the Galen or ToT storylines, though, since a friend of mine (also on PC-NA) who also owns Firesong tells me that a character of hers who has never been to Galen and never touched Tales of Tribute does see these two clues as unread, while a character of hers who has been to Galen and done Tales of Tribute (but not completed either storyline) does not see them at all, even as unread, like my alt.
Whatever the check is, it is clearly character-specific when it should be just an account-wide check for access to Firesong.