I'm Cesress, from Sethraliss Server. (Sorry for the bad English).
I found a quest named Study Hall: Combat Research, from Azsuna Questline (Legion Quests) is bugged.
The Quest asks to obtain 3 books from the Hall of Arcane Learning, each book contains a challenge. The problem starts after the first book - the first challenge. Whenever I surpass the first one, I can't play the second and the third one.
Here are 2 screenshots, when i play the second book, it still appears the first challenge. It's also appear when I play the third one, too