Pagination suffix & reuse_query_string problem

And once again, depending on these lines from manual if I will set $config['reuse_query_string'] = TRUE:

By default your Query String arguments (nothing to do with other query string options) will be ignored. Setting this config to TRUE will add existing query string arguments back into the URL after the URI segment and before the suffix.:

taken from: http://www.codeigniter.com/user_guide/li...ation.html

the $config['suffix'] should be added after QUERY_STRING, but it doesn't.

Let's take a look on 474 line from system/libraries/Pagination.php:

Code:

// Standard segment mode.
// Generate our saved query string to append later after the page number.
if ( ! empty($get))
{
    $query_string = $query_string_sep.http_build_query($get);
    $this->suffix .= $query_string;
}

And we will see $this->suffix .= $query_string; instead of $this->suffix = $query_string . $this->suffix;

Is that a bug, or I simply don't understand this thing?
Could somebody help me, please?