White lines between elements of a Spline Component

Based on the tutorial for Spline components in the official Unreal Engine Youtube Channel: Using Splines & Spline Components | Live Training | Unreal Engine - YouTube
I made some modifications to be able to build the pedestrian path in the middle of a wide avenue. However, I noticed that, when I zoom out from it, white lines begin to appear in between the meshes. Any idea of why this could be happening?