Choosing the option to Unlink OneDrive does not disable it at startup. There is another checkbox in the settings dialog, I can't remember what tab at the moment, that you uncheck to keep it from starting when Windows starts.
All of the above being said, it appears that somehow the "Run as Administrator" property has been set either on the shortcut that's being used to invoke OneDrive or on the OneDrive program itself (I'd suspect the former).
If you go into settings and uncheck the setting I mentioned I suspect this will stop happening, but should you ever wish to reactivate OneDrive you'd still be getting this issue. I would check to see where OneDrive is getting invoked from to uncheck that "Run as Administrator" property before doing the don't start when Windows starts change if you ever intend to use OneDrive in the future.
Brian AKA Bri the Tech Guy (website in my user profile) - Windows 10 Home, 64-Bit, Version 1803, Build 17134
Memory is a crazy woman that hoards rags and throws away food.
~ Austin O'Malley