Dear Seiya Ryusinbasi refers to the following article for the reason. The main reason for the changes in XRD intensity at room temperature it occurs mostly amorphous state compared to dried one.
Article Synthesis of NaX zeolite: Influence of crystallization time,...
Absorption matter into a zeolite changes the structure factor. But also the peak-width may change (e.g. due to a d-spacing distribution). Peak height is not a good quantity measure reflection intensity. The peak area is the more meaningful quantity.