Below are the known issue that occurred after the December 29th maintenance.
It has come to our attention that the NPC was missing. This will be fixed tomorrow. Additional information will be announced tomorrow.
Additional information regarding One Skill Kill Issue
Some users deals too much damage to dungeon bosses and results in not completing the dungeon quest. This is a known issue that rarely happens when killing the boss too quickly. Please be advised to avoid doing too much damage at once to avoid this issue.
Thank you for your understanding.