It has come to our attention that some users cleared the last boss in the Halloween Attraction dungeon, but it didn’t complete the dungeon quest. This is a known issue that rarely happens when killing the boss too quickly.
If you have experienced this during your Halloween dungeon run, contact us at https://www.closersonline.com/support/qna/. Be reminded to choose ‘Game Play‘ as category and ‘Bug/Error‘ as your Inquiry category. Please provide us the details such as the time when it occurred and a full screenshot of your character where the quest didn’t complete after finishing the last stage.
Thank you for your understanding.