MacOS High Sierra 10.13.1
When the Application Frame is disabled, the menu items are displayed incorrectly. The "View" menu is attached.
I have reset the preferences and the menus seemed to work fine, but when I disabled the application frame, they went crazy again.
Also discussed on Twitter with Customer Care. https://twitter.com/scottzirkel/status/928392054660530176
Thanks for reporting the issue. Illustrator team appreciates this.
We are able to repro this issue at our end.
With Best Regards,