On Tue, 13 Mar 2018 11:28:45 +0900, Katsumi Yamaoka wrote:
> +	;; Remove extra bytes in utf-8 encoded data.
> +	(when (eq coding 'utf-8)
> +	  (goto-char (point-min))
> +	  (while (re-search-forward "[\x00-\x7f]+\\([\x80-\xbf]\\)" nil t)
> +	    (replace-match "\\1")))

Corrected: