ACF does not allow specific fields to be added to screen options. ACF should be showing the field group title with a check box to show or hide the group. A selection would have to be made in that field in the field group. If you want to add a custom field to screen options you’d need to use some other method, but I do not believe that fields added here will be saved in a way that is related to the current post, these are saved for the current “screen” for the current user only.
