First of all: Hello everyone, it's great to be part of the preview :)
I've been tinkering with some basic shapes in order to get my head around the Blender > Sansar workflow. For the most part it's been smooth sailing, but I've come across one issue that I can't seem to figure out.
The spheres in the image below are geometrically identical, basic UV spheres with a single seam around the equator. The red one has no texture map, just a solid color; the back left one was not triangulated prior to upload, while the front one was.
What they have in common is a shading error along the diagonal that runs through the highlight. The error is stationary, i.e. it doesn't move with viewing angle or light source position. It's also not an artifact on the diffuse map.
The material has diffuse, rough and metal channels; the latter two are simply flat grayscale textures. Removing them does not seem to have any impact on the issue.
What am I doing wrong? Any help would be greatly appreciated.