Coordinate woe OnPostRender/OnGUI, immediate draw?

"Coordinate system changes between OnPostRender and OnGUI while in immediate draw mode"

Hi, i am running in to a strange problem, where The co-ordinate system changes completly between OnPostRender and OnGUI of the same script. It seems like OnPostRender follows World coordinate system and OnGUI follows Screen coordinate system.

I guess u will understand from the following code,

 void OnPostRender()
     {
         if(Event.current.type == EventType.repaint)
         DrawCircle();
     }
     
     void OnGUI()
     {
         
         DrawCircle();
     }
     
     
     
     void DrawCircle()
     {
         zValue = transform.position.z+1;
             
             GL.Begin(GL.LINES);
             GL.Color( new Color(1,0,1,1f) );
             
             for(int i=1;i<360;i+=6)
             {
                 GL.Vertex3 ( 0 + Mathf.Cos ((i-1)*Mathf.Deg2Rad)*radius, 0 + Mathf.Sin((i-1)*Mathf.Deg2Rad)*radius,zValue);
                 GL.Vertex3 ( 0 + Mathf.Cos (i*Mathf.Deg2Rad)*radius, 0 + Mathf.Sin(i*Mathf.Deg2Rad)*radius,zValue);
             }
             
             GL.End();
     }

this script is attached to an orthographic camera, where i am getting 2 different circles. one at the top of the screen and one at the middle of various size, though the radius is the same.

Is it a bug or is this the way GL functions work in unity. Is there a possibility of making it use one fixed co ordinate system.