That's not a bug. It does exactly what it is designed to do....
If you only want to start up Plus! then don't use the parameter /Winstart.
See these posts for more details:
(if you put those two posts together, you'll have your answer (too tired now to explain everything again in detail in another way
)
CookieRevised's reply to Startupmonitor issue
CookieRevised's reply to Force Plus to load