Hi guys! I just looked through my book-related achievements and clicked on the Learn a Language - show requirements button. Suddenly, it lit up green, and I got an alert for achieving this, although only one book was actually marked as "read". I was already confused and went to open up my pets books page. When I "manually" went back, the achivement was red again. Then I thought, well, let's just buy the books, but decided to look up which books I really needed. Turns out:

TL;DR: I have read to my pet all the needed books for the Learn a Language, but only one book is marked as read, and I did get the achievement, but now it's gone again after a re-fresh. Still only one book is green. Should I just file a ticket? I was unsure and wanted to first ask in the forums ^^'

I just went back and flipped through all my pets book-pages and went back to the achievement page and now it's there. All the books are marked green, too. I didn't get an alert or any other notification this time, though. Maybe the system just hiccuped :D