В каждой бочке затычка

Is this puzzle broken? I solved it once and got A Copper Key but didn't see any chest to open with the key and then solved it a few more times to try to get the chest to spawn but each subsequent solve teleported me to a plateau near Ironroot Draw part of Scarlet Gorge at coordinates 4860, 4297. EDIT: After discarding the Copper Key and redoing the puzzle the chest appeared and I was able to get the achievement.