I can confirm this, the Dash/Ubuntu icon does change with the default themes, but not with user installed ones. When changing the icon theme, the panel icons will change but the Dash/Ubuntu one will still be whatever the last icon theme made it.
Current workaround: Changing the window controls seems to refresh it and change it to what the current icon theme is.
I can confirm this, the Dash/Ubuntu icon does change with the default themes, but not with user installed ones. When changing the icon theme, the panel icons will change but the Dash/Ubuntu one will still be whatever the last icon theme made it.
Current workaround: Changing the window controls seems to refresh it and change it to what the current icon theme is.