The Shortcuts by default are public Shortcuts. This would mean that everyone in the workspace will have access to the Shortcut. While they might have access to the Shortcut, it does not mean they will automatically receive the access to the underlying document.
You can create a private Shortcut (visible only to you) by enabling the Private toggle in the extension window. These private Shortcuts start with o/my.
You can also create a collection and ensure that only a custom defined group has access to it.