Default window manager styles cut off the top of application icons in the title bar when window is maximized

Using Xfce 4.20 on openSUSE Tumbleweed and Slowroll.

The three Default window manager themes (Default, Default-hdpi and Default-xhdpi) are cutting off the top of application icons on the left side on the title bar, when a window is maximized.

If the window is made smaller but not minimized, the icon is correctly centered. Please see attached images showing both cut off and correctly centered. The example icon used is for Chromium, but this occurs with any application icon.

Note that in two of the images, the Xfce panel appears superimposed over the Chromium icon, this is because I have the panel set to be transparent.