The reason for the deposits is due to the fine texture of the Ganoderma Spores. The finer the powder the greater the chance of blending with the other ingredients in the coffee, thereby, forming a deposit which results in the grainy residue observed at the bottom of the cup.
Due to the Ganoderma being a natural ingredient, variances in texture and appearance can occur periodically.
The suggestion is a more vigorous mixing with hot water at the beginning and perhaps half way through the cup will help dissolve the contents of the sachet.