> -   (cons (current-buffer)
> -	 (current-window-configuration)))
> +   ;; This doesn't work, gives wrong-type-argument listp when quitting.
> +   ;; (cons (current-buffer)
> +   ;;       (current-window-configuration))
> +   )

Ooops, sorry, I was confused about this.  This part is fine.

> +      (gnus-read-ephemeral-emacs-bug-group bugid (current-window-configuration)))))

It's this one that is missing the cons.  Patch updated.