Jo'Karr says 'invaluable knowledge has been lost' even when given the tome

If the player chats with Jo’Karr after their ‘quest’ for him has finished (either the player has given the tome to Jo’Karr, or the player has destroyed/harvested the tome instead), Jo’Karr always seems to deliver this same line of dialogue.

I assume this is the intended dialogue if the tome has been destroyed; but the dialogue doesn’t make sense if the player has given the tome to Jo’Karr.