After mixing the luminous powder with the paste in the printing industry, the viscosity of the paste is reduced, and after the paste is thickened, the viscosity cannot be increased. Why?

This situation may occur if the paste is water-based and a non-waterproof glow powder is used.
If it is because of the phenomenon caused by our single variable luminous powder, it is that there is a substance in the paste that reacts with the luminous powder. This reaction changes the PH value of the printing paste. In addition, the thickening method he uses is likely to be fumed silica. It reacts with luminous powder.