Mektul, THe Forgemaster

This is probably not intentional, but after the boss first falls to his knees, you can move behind him, and he will try to run away from you while also attempting to reach the molten gold to begin his lava attack. This results in him running around aimlessly because you are "blocking" his path to the molten gold. I was using the "Rhoa Mount" spirit gem, which might be contributing to this issue.