Issue: Incorrect string value:

	public function mb_clean($input)
	{
		$utf8 = '#([\x09\x0A\x0D\x20-\x7E]' .		# ASCII
			'|[\xC2-\xDF][\x80-\xBF]' .				# non-overlong 2-byte
			'|\xE0[\xA0-\xBF][\x80-\xBF]' .			# excluding overlongs
			'|[\xE1-\xEC\xEE\xEF][\x80-\xBF]{2}' .	# straight 3-byte
			'|\xED[\x80-\x9F][\x80-\xBF]' .			# excluding surrogates
			'|\xF0[\x90-\xBF][\x80-\xBF]{2}' .		# planes 1-3
			'|[\xF1-\xF3][\x80-\xBF]{3}' .			# planes 4-15
			'|\xF4[\x80-\x8F][\x80-\xBF]{2})#S';	# plane 16

		$string = '';
		$matches = array();

		$pcre_limit = $this->pcre_limit;

		if ($pcre_limit AND strlen($input) > $pcre_limit)
		{
			$chunks = str_split($input, $pcre_limit);
		}
		else
		{
			$chunks = array($input);
		}

		foreach ($chunks AS $chunk)
		{
			while (preg_match($utf8, $chunk, $matches))
			{
				$string .= $matches[0];
				$chunk = substr($chunk, strlen($matches[0]));
			}
		}

		return $string;
	}

	public function mb_clean($input, $replace = '')
	{
		$utf8 = '#([\x09\x0A\x0D\x20-\x7E]' .		# ASCII
			'|[\xC2-\xDF][\x80-\xBF]' .				# non-overlong 2-byte
			'|\xE0[\xA0-\xBF][\x80-\xBF]' .			# excluding overlongs
			'|[\xE1-\xEC\xEE\xEF][\x80-\xBF]{2}' .	# straight 3-byte
			'|\xED[\x80-\x9F][\x80-\xBF]' .			# excluding surrogates
			'|\xF0[\x90-\xBF][\x80-\xBF]{2}' .		# planes 1-3
			'|[\xF1-\xF3][\x80-\xBF]{3}' .			# planes 4-15
			'|\xF4[\x80-\x8F][\x80-\xBF]{2})#S';	# plane 16

		$string = '';
		$matches = array();

		$pcre_limit = $this->pcre_limit;

		if ($pcre_limit AND strlen($input) > $pcre_limit)
		{
			$chunks = str_split($input, $pcre_limit);
		}
		else
		{
			$chunks = array($input);
		}

		foreach ($chunks AS $chunk)
		{
			while ($chunk AND preg_match($utf8, $chunk, $matches, PREG_OFFSET_CAPTURE))
			{
				if ($replace AND $matches[0][1])
				{
					$string .= str_repeat($replace, $matches[0][1]);
				}

				$string .= $matches[0][0];
				$chunk = substr($chunk, strlen($matches[0][0]) + $matches[0][1]);
			}

			if ($replace AND $chunk)
			{
				$string .= str_repeat($replace, strlen($chunk));
			}
		}

		return $string;
	}

	public function verify_utf8(&$text)
	{
		$regex = '/[\x00-\x08\x10\x0B\x0C\x0E-\x19\x7F]';
		$regex .= '|[\x00-\x7F][\x80-\xBF]+';
		$regex .= '|([\xC0\xC1]|[\xF0-\xFF])[\x80-\xBF]*';
		$regex .= '|[\xC2-\xDF]((?![\x80-\xBF])|[\x80-\xBF]{2,})';
		$regex .= '|[\xE0-\xEF](([\x80-\xBF](?![\x80-\xBF]))|(?![\x80-\xBF]{2})|[\x80-\xBF]{3,})/';

		$text = preg_replace($regex, '?', $text);

		$regex = '/\xE0[\x80-\x9F][\x80-\xBF]';
		$regex .= '|\xED[\xA0-\xBF][\x80-\xBF]/S';

		$text = preg_replace($regex, '?', $text);
	}

	public function verify_utf8(&$text)
	{
		$text = vw_Hard_Core::model('String')->mb_clean($text, '?');
	}

while ($chunk AND preg_match($utf8, $chunk, $matches, PREG_OFFSET_CAPTURE))

while ($chunk !== '' AND preg_match($utf8, $chunk, $matches, PREG_OFFSET_CAPTURE))

$ascii_only = mb_check_encoding($source_text, 'ASCII');

if (!$ascii_only)
{
// contains non-ASCII characters
}