Hi, thanks for the feedback and reporting the bug! May I ask if you've completed the game, and whether the books still remained unfinished? Also can you tell me which books have duplicates if you haven't reset the game?
I did complete it! It wound up being my mistake--the other "Clay Tablets" was supposed to be pottery instead of language! (And I missed that the box didn't flash red haha). Thanks for creating such a charming little game and good luck!