AWS SES is treating vacation responder as bounce

We use aws server and our application sends emails to customers via Amazon's Simple Email Service (SES).

When recipients turn on vacation responder, SES treats them as bounces and blocks that email id after few sends.

Is this a standard problem of SES or I am missing something? Any help would be appreciated.

This is how my PHP code is sending email via ses

define( 'AWSAccessKeyId', $this->SNS_Access_Key_Id );
define( 'AWSSecretKey', $this->SNS_Secret_Key_Id );

$transport = Swift_AWSTransport::newInstance( AWSAccessKeyId, AWSSecretKey );
$transport->setDebug( true ); 

$mailer = Swift_Mailer::newInstance( $transport );

$message = Swift_Message::newInstance()
                ->setSubject( $email_subject )
                ->setFrom( array( $from_email_id ) )
                ->setTo( $to_email_id_array ) 
                ->setBody( $email_body, 'text/html' );

$response = $mailer->send( $message );