I have this code
$ch = curl_init(); curl_setopt($ch, CURLOPT_URL, $url); curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); curl_setopt($ch, CURLOPT_HTTPHEAD
I encountered the same issue when developing my library for accessing their JSON API. In the code that handles the response I had to strip those characters out in order to properly decode the string as JSON.
Line 113:
$this->responseJson = preg_replace('/[\x00-\x1F\x80-\xFF]/', '', $responseJson);