Hello Nick, and welcome to Seven Forums.
Technically Quick Launch
is a taskbar toolbar and not a pinned item. This is why when you open/run a item from Quick Launch, it will still have a separate icon appear on the taskbar for it's opened window. There's nothing that you could do about this other than pinning the item/program
in Quick Launch on the takbar itself instead. This way you could run it from the taskbar instead of Quick Launch.
Hope this helps,