Air 19.0 PushNotificationEvent.PUSH_NOTIFICATION_RECEIVED_EVENT not received when triggered by PHP API

I am building an iOS app and generating a server side notification request with the PHP API. the notification is received fine (I can see it popup) when the app is active. but the PushNotificationEvent.PUSH_NOTIFICATION_RECEIVED_EVENT is not fired. when sending a test push through the control panel, the PushNotificationEvent.PUSH_NOTIFICATION_RECEIVED_EVENT is fired fine and i can see the trace.

where did I go wrong? here's my code:

pushwoosh = PushNotification.getInstance();
trace("::::" , pushwoosh.isPushNotificationSupported);  // trace is true
pushwoosh.addEventListener(PushNotificationEvent.PERMISSION_GIVEN_WITH_TOKEN_EVENT, onToken);
pushwoosh.addEventListener(PushNotificationEvent.PERMISSION_REFUSED_EVENT, onError);
pushwoosh.addEventListener(PushNotificationEvent.PUSH_NOTIFICATION_RECEIVED_EVENT, onPushReceived);

pushwoosh.onDeviceReady();
pushwoosh.registerForPushNotification();

var pushToken:String = pushwoosh.getPushToken();
if(pushToken == null)
{
    trace( "\n Push TOKEN: not registered" );       
}
else
{
    trace( "\n Registered for pushes: " + pushwoosh.getPushToken() + " ");
}
trace("\n Pushwoosh HWID: " + pushwoosh.getPushwooshHWID() + " ");

// listeners
public function onToken(e:PushNotificationEvent):void{
    trace( "\n TOKEN received: " + e.token + " ");              
}
public function onError(e:PushNotificationEvent):void{
    trace("\n TOKEN error: " + e.errorMessage+ " ");
}
public function onPushReceived(e:PushNotificationEvent):void{
    trace( "\n Push Received: " + JSON.stringify(e.parameters) + " ");
}

Which, as you can see, is identical to the example app. and my php code:

function sendNotification($lang , $message , $device)
{
    $this->pwCall('createMessage', [
                                'application' => 'XXXXX-XXXXX',
                                'auth' => 'xxxx',
                                'notifications' => [
                                                    [
                                                        'send_date' => 'now',
                                                        'content' =>  [ 'test'],
                                                        'data' => ['custom' => 'json data'],
                                                        "platforms"=> [1],
                                                        "ios_badges"=> 1,
                                                        "ios_sound"=> "sound.caf",
                                                        "ios_ttl"=> 3000,
                                                        'devices' => [ $device  ]
                                                ]
                                            ]
                                ] 
    );
}

function pwCall($method, $data )
{
    $url = 'https://cp.pushwoosh.com/json/1.3/' . $method;
    $request = json_encode(['request' => $data]);

    $ch = curl_init($url);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, true);
    curl_setopt($ch, CURLOPT_ENCODING, 'gzip, deflate');
    curl_setopt($ch, CURLOPT_HEADER, true);
    curl_setopt($ch, CURLOPT_POST, true);
    curl_setopt($ch, CURLOPT_POSTFIELDS, $request);

    $response = curl_exec($ch);
    $info = curl_getinfo($ch);
    curl_close($ch);

    print "[PW] request: $request\n";
    print "[PW] response: $response\n";
    print "[PW] info: " . print_r($info, true);

}