It is normal for this kind of agglomeration to occur. It belongs to pure physical action and can be called "soft agglomeration".
"Soft agglomeration" can be solved by simply grinding and sieving.
The more serious problem may be that the drying temperature is too high as the high temperature may enhance the powder activity, resulting in easy caking.
It may also be that the choice of grinding aids is incorrect. Different materials use different grinding aids, using water, ethonal or other solvents, there will be different results depending on the material characteristics.