I moved my gear from Monk to Huntress to check how much damage she does, and found out that Huntress auto attacks stack and deals bonus damage from Crane Stance. I haven't checked everything but it looks like it only works with elemental weapons. I got best results with penta 4x bow with water element (dps went from 46k-58k to sick 148k-170k). It worked on single earth and triple earth bows as well but not on bow with ability power. If it's problem with elemental damage it probably work on all heroes, not only Huntress.