Like the bewitching hour bug.
the Crane Stance sphere is proc'ing from elemental damage, from things like the element damage one can get as a secondary on a weapon, and the lightning from the storm gloves.
Its a fun mechanic, but clearly not intended.
Gear that is causing Crane Stance to proc:
Damage break down:
Crane stance is proc'ing from the following:
Crane stance should only be proc'ing from secondary RMB attacks.