I was finally able to locate and recreate the problem. It’s caused by an invalid mesh.
The mesh has some short edges. I created the mesh union in Grasshopper so I don’t necessarily see that there might be a problem…
The component which causes the invalid mesh in my file is from Kangaroo. Maybe I should have used Align Vertices instead. It seems to work.
invalid_mesh_pink_dots_problem.gh (210.3 KB)