To solve pink PlaneFinding Grid material in editor, open PlaneFinding_Grid shader and coment theese lines.
Hello e_scanta, thank you for posting this solution. I was able to reproduce the shader issue found in the PlaneAnchors scene, and resolve it as you mentioned, through excluding the shader from DX11 by commenting out line: 25 of the PlanefindingGrid.Shader. The shader can be found in Assets > ARDK > Extensions > Planefinding > PlanefindingGrid.shader.
//#pragma exclude_renderers d3d11.