magento2 – Magento 2.3 – Why observer triggers multiple times on ‘newsletter_subscriber_save_after’ event?

I am trying to send email when customer subscribes/unsubscribes from newsletter, however, my observer is triggering three times for some odd reason. Any ideas why or how to prevent it?

The following code logs “Test” three times in the log files…


namespace VENDORMODULEObserver;

use MagentoFrameworkEventObserver as EventObserver;
use MagentoFrameworkEventObserverInterface;
use PsrLogLoggerInterface as Logger;

class NotifyAdmin implements ObserverInterface
    public function __construct(
        Logger $logger
    ) {
        $this->_logger = $logger;

    public function execute(EventObserver $observer)