Displacement Tessellation on Edge of Mesh Blurred?

Hello all,

I have a problem with my mesh (no bevel just ordinary subdivided 10x10 cube exported from maya), I have tried ticking the crack free setting in the material editor for this material and also PN Triangle / Flat tessellation but still when setting tessellation strength with my custom parameters the expanding tessellation of my mesh shows a blurry bevel?

Here is a screenshot to the problem,
thank you.