Problem with offset when having high values in the Stone size and Density "histogram"

[oskarlin]

I want my scree to be quite sparsely scattered on my maps but when I move the stone size and density curve to the top to the right I achieve what I want in terms on density but instead there is a strange offset from north. See attached images. One with the curve maxed and one not.

If this isn't a bug, then how do I achieve these more sparsely scree?