Comment 4 for bug 1704893

The JournalErrors.txt above have lot of "xfce4-notifyd[6564]: Theme parsing error: gtk-widgets.css"

is it still happening ?

When you said 'fresh install' does that mean you are not reusing a shared old /home which can contain old borked settings ?

Have you added external sources / custom settings ?

Note that no one else have met that issue on launchpad; so something is unusual on your installion.