(Novice question) Distortion at the edge of the static mesh, why?

Hi, just been creating a static mesh to use inside unreal and have discovered that when implementing them in the level there are marks or distortions at the edges of each mesh, can someone clarify what this might be and how i can fix it? I have tried using a differently constructed mesh but I get the same result - (working in Houdini if that’s relevant)


have you rebuilt lighting?