Hi,
Actually, because of the uploaded image size, it's hard to say what's happening. I would suggest you to check your
Direction settings under
Surface tab (probably is set to 100). In case of large clumps I would recommend you to set it to Surface's
Normal (0) and even you can take advantage of
Scale to fit sloped area option. You can find more about these setting in our
on-line reference guide.
Also please double check you don't have any
Random Translation for Z axis enabled in
Transform tab.
Best regards,