RabbitMQ consumer gets doubled after sometime

Question

We are using RabbitMQ v3.7.5, AMQP 0.9.1, Erlang 20.1.7.1, PHP 7, centos 7

Our consumers are written using php-amqplib v2.9.1

We start our consumers by calling a URL using curl. The consumers work as expected for sometime, but after sometime all consumers gets doubled i.e it shows two connection running for same consumer. Once this happens, none of the consumers respond when there is data on the queue but all the data received on the queue is lost.

Has anyone faced the same issue?

Consumer Code (I am using the same code given on the official site: https://www.rabbitmq.com/tutorials/tutorial-two-php.html)

require_once __DIR__ . '/vendor/autoload.php';
use PhpAmqpLib\Connection\AMQPStreamConnection;

$connection = new AMQPStreamConnection('localhost', 5672, 'guest', 'guest');
$channel = $connection->channel();

$channel->queue_declare('task_queue', false, true, false, false);

echo " [*] Waiting for messages. To exit press CTRL+C\n";

$callback = function ($msg) {
    echo ' [x] Received ', $msg->body, "\n";
    sleep(substr_count($msg->body, '.'));
    echo " [x] Done\n";
    $msg->delivery_info['channel']->basic_ack($msg->delivery_info['delivery_tag']);
};

$channel->basic_qos(null, 1, null);
$channel->basic_consume('task_queue', '', false, false, false, false, $callback);

while (count($channel->callbacks)) {
    $channel->wait();
}

$channel->close();
$connection->close();

Expected Result: The consumer should not be duplicated.