Did you ever stop to consider that there is an order in which the pylons must be killed to fully clear his buff? Running ahead and killing one out of order always stops the debuff from counting down.
First transition: Drop down west, kill pylon, kill pylon directly across, drop down and kill pylons as you come across them.
Second transition: Drop down west, kill pylon, drop down, kill pylon, kill pylon to the north, kill the rest as you pass them.
Works every single time. And killing them in the wrong order results in the buff still being up every single time.