Yep, absolutely sure it's unmodded. Steam updated to 0.90, played for a bit (only mod was mechjeb), crashed a few times, so I wiped all KSP files and did a fresh install with Steam. Haven't installed any mods since the fresh install. From a little farther away, the Mun didn't have any triangles at all, it was a pure ball of color. Quite beautiful. Only when I got closer did the triangles start rendering.