What is it? Different render with same render node. Render in Mplay and Render view.
Comments?

The Render Viewer will automatically switch the rendering engine on the ROP from micropolygon to raytracing when its “Preview” toggle is enabled. This is because preview rendering is only supported by the raytracer. Mplay will not do this conversion since it does not render in preview mode. Thus, one of your renders is being raytraced while the other is being rendered with micropolygons, and the micropolygon render is producing more noise. Likely you will need to increase the sampling quality on your lights when rendering with micropolygons, or switch the renderer on your ROP from micropolygon to raytracing.

Thank you very much!