BOSS talent point bug

First, I fought the level 79 and 80 BOSS normally, and obtained the talent book after success. Then I fought the level 82 BOSS first, and successfully obtained the talent book. Finally, I fought the level 81 BOSS. In the Crimson Coast map, after I defeated the lava BOSS, this BOSS did not drop anything. Then I fought the level 81 battle again. After completing it, there was a normal drop, but no talent book was dropped.