I am trying to find out what is causing the white grid lines on the material. This using the default textures as Virtual Textures from megascans materials. When I use this world aligned material in the map, all meshes that use it have this white grid.
From what i can tell, the default texture as a virtual texture is what is causing the lines to appear, maybe you can try changing the default material for the virtual textures for a black texture, or turning off the virtual texture and see if that makes the lines to disapear