Maximum combined torque on the axis occurs when the draconic month maximum declination aligns with a solstice. This happens at precisely the same frequency as the Chandler wobble. If this is not an additive stimulus and is simply a coincidence, I don't know what to say.

*The Devil's Advocate View* : The Chandler wobble, QBO, ENSO periods are all coincidences with respect to lunisolar cycles apparently.