Let me guess, you looked up while you were walking around in either the Strand, Spine, or the Gardens? Go to the Divalian Mists, Rheasilvia, and look up again. The tower, green smoke, and singularity aren't visible from Strand or the Gardens but are visible from the other two areas. Given I can see the skybox change when moving from Divalian to Spine of Keres, it is likely a skybox issue. Same for anything within the Ascendant Plane. EDIT: broggie probably answered the question already.