Artifacts / Stretch Marks in Mesh Manipulation

I applied a uniform mesh manipulation to a default Unity sphere, but there are always these sharp edges that look like artifacts - it's a spherically symmetric object to start with, so I am not sure where the "stretch marks" or artifacts come from.

Is there a way to get rid of these sharp edges? What is causing them? Are there phantom poles?

Snippet is from MeshFilter page, but with the manipulation being set to Vector[p].y, instead of random.