I hit the same issue! CesiumDefaultTileSetMaterial could use some fixing. Or at least Cesium could add a “Simple Lit” basic shader or the likes. Also the normals are not rendered correctly it seems. They are not facing up in unity coordinates system, depending on where you are on the globe. Not sure why? It took me a while but I ended up writing my own shader using Toony Colors Pro addon that removed “Ramp Shading” from the shader. That fixed the issues of tiling. You can see my post from earlier here: Generate Smooth Normals causes tile artifacts - #2 by janine