@luckyscout I think I figured it out. (SL on left, Blender on right)
In blender, I copied the normals from a T-posed version of the model to this posed one, and it ended up looking very similar to SL.
I think SL uses the normals from the un-posed model and doesn't update them when the model deforms like blender does.
I think the only solutions are:
-Smooth that part of mesh
-Make a normal map texture
-Data transfer normals from an A-posed version of the body
(1/2)
@mileskitaro if anyone fixed that for me it would be YOU
@luckyscout before and after data transfer, using a stark windlight to tell the difference.