Morphological Transformation Artifacts

MT is fast so I'd like to use it for some images, but I can't seem to find a way to eliminate artifacts. 

Here is a nonlinear image:



I've tried changing lots of settings but so far unable to elimiate the dark purple pixilated artifacts that appear all over the image, and every image I've tried to process with. 

Anyone have the same issue and found a way to use MT without these unwanted artifacts?

Thanks!
Jerry