Initially icons are rendered properly in OptionPane demo of SwingSet2 with MetalLookAndFeel with metal pipeline.

Go to SwingSet2 Demo.
Click on Look & Feel tab and select Java Look & Feel
Go to JOptionPane Demo
Click on "Show Input Dialog" and check the icon on the left side.
Click on "Show Warning Dialog" and check the icon on the left side.
They are not correctly rendered.
But we can see that after checking 2 or 3 time they appear correctly.