em_event_save result is null and event empty

I am using the following code in my theme’s function.php file:

add_filter('em_event_save', 'pddSaveCourseEventAssociation');
function pddSaveCourseEventAssociation($result, $event) {
    echo "<pre>";
    var_dump($result);
    var_dump($event);
    echo "</pre>";
    exit();
}

When I save an event, the var_dumps() above result in “true” and NULL. Is there a reason the $event argument is NULL? The save works fine if I let it go through (remove the exit). Not sure what I might be doing wrong; any help would be appreciated. I am basing this on a look at the code and the page here: https://wp-events-plugin.com/tutorials/saving-custom-event-information/.

Cheers

https://www.ads-software.com/extend/plugins/events-manager/