diff --git a/source/blender/gpu/shaders/gpu_shader_3D_polyline_geom.glsl b/source/blender/gpu/shaders/gpu_shader_3D_polyline_geom.glsl
index b28205b349e..cca94680284 100644
--- a/source/blender/gpu/shaders/gpu_shader_3D_polyline_geom.glsl
+++ b/source/blender/gpu/shaders/gpu_shader_3D_polyline_geom.glsl
@@ -26,7 +26,8 @@ void do_vertex(const int i, vec2 ofs)
   finalColor = color;
 
 #elif defined(FLAT)
-  finalColor = finalColor_g[0];
+  /* WATCH: Assuming last provoking vertex. */
+  finalColor = finalColor_g[1];
 
 #elif defined(SMOOTH)
   finalColor = finalColor_g[i];