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,
Shawn