Webhooks end point calling multiple times with different Topics by mo zap

Hi ,

I am developing an application where I am using API level webhooks

topics = ["orders/create", "orders/updated", "orders/cancelled", "refunds/create", "orders/fulfilled", "app/uninstalled"]
topics.each do |topic|
   	webhook = ShopifyAPI::Webhook.new(:format => "json", :topic => topic, :address => "https://example.com/webhooks/API.php")
    raise "Webhook invalid: #{webhook.errors}" unless webhook.valid?
    puts webhook.persisted? # => false
    webhook.save
end

Webhooks are registering and was working before perfectly 

Now I see strage issue in my API.php file and using the following line I am getting the Shopify Event 

$event = $_SERVER['HTTP_X_SHOPIFY_TOPIC'];

Now when I create a new order at store It ($event) should send only orders/create, where as It is sending the following events. Along with Evvent I am adding the time stamp also.

API.php file 

<?php
    $now = date("Y-m-d H:i:s") . substr(microtime(), 1, 9);
    $myfile = fopen("data.txt", "a") or die("Unable to open file!");
    $event = $_SERVER['HTTP_X_SHOPIFY_TOPIC'];
    fwrite($myfile, "$event event at $now \n");

    fclose($myfile);
?>

data.txt file - API.php output 

orders/updated event at 2015-03-09 07:03:57.95089500
orders/updated event at 2015-03-09 07:03:58.14732300
orders/create event at 2015-03-09 07:03:58.24107500

Please help to find where the problem is, whether in API file or from App side.

Thanks,

MO