It appears to be a race condition, like maybe nm-applet first registers itself in the tray, then indicator-applet-complete is loaded, and it shows nm-applet a second time. While if nm-applet starts after indicator-applet-complete has finished loading, it doesn't register itself in the tray, only in the indicator-applet-complete itself.
But I'm experiencing this very rarely so I can't easily test workarounds.
If you add "X-GNOME-Autostart-Delay=10" in /etc/xdg/autostart/nm-applet.desktop, does the problem go away?
It appears to be a race condition, like maybe nm-applet first registers itself in the tray, then indicator- applet- complete is loaded, and it shows nm-applet a second time. While if nm-applet starts after indicator- applet- complete has finished loading, it doesn't register itself in the tray, only in the indicator- applet- complete itself.
But I'm experiencing this very rarely so I can't easily test workarounds.
If you add "X-GNOME- Autostart- Delay=10" in /etc/xdg/ autostart/ nm-applet. desktop, does the problem go away?