I encountered the same issue than joe dot bowman at edigitalresearch.com
Even if i read on the web that it is a usual issue when using PHP 5.6 and upper, i didn't encounter it on every sites on which i use PHP 5.6.
Nevertheless, i had to find a solution because, when the issue appears, it's embarrassing. This is what i found thanks to Alexandra López on http://hasibul.info.
Instead of :
if (function_exists('iconv'))
{
// These are settings that can be set inside code
iconv_set_encoding("internal_encoding", "UTF-8?);
iconv_set_encoding("input_encoding", "UTF-8?);
iconv_set_encoding("output_encoding", "UTF-8?);
}
i use :
if (PHP_VERSION_ID < 50600) {
iconv_set_encoding('input_encoding', 'UTF-8');
iconv_set_encoding('output_encoding', 'UTF-8');
iconv_set_encoding('internal_encoding', 'UTF-8');
} else {
ini_set('default_charset', 'UTF-8');
}