I have been advised the reason sometimes you get marijuana with excessive powdery residue, that kinda looks like thicker kief, is due to all the additives and ferts some people put in their nutes. Like silicon potassium, and I have heard of another additive that increases yield and taste. Brix+. It seems to make sense to me. Certain marijuana always leaves behind this pile of powdery residue, and it's never great, imo.