Interesting. I’ve never encountered an issue like this so I have no idea what to try, sorry. I’m at Win10 x64 too but I can log in without issues.
That probably means you somehow have 2 CIUs installed at once, one for v85 and one for the newer version, and your shortcut leads to the older one. Try typing “CIU” in the search bar and look if it shows you more than one game. You can also look in installed apps list through either control panel or default “Settings” thing.