Strange triangles appear after using Rock Generator and scattering on surface

Hey Guys,
I started using the rock generator and afterwards the scattering tool to sprinkle my stones over a flat surface with numerous subdivisions but after I hit command (enter) these strange triangles appear. Anyone a solution ?

Thanks a lot for the support

greetings

Related to the addon it sure seems like it can be a bug. See if you can find the developer in this forum to mention it.

In the meantime just to get going with your work check this thread.

Technique for a pile of soil?