Lightbox only loading the clicked image of gallery

This was working great before, but now for some reason when I have a gallery (using ACF Gallery), when you click an image, it opens in a lightbox but doesn’t let you move to the next image.
I have auto play on, and it just repeats the same image.

Is this an issue with the latest update?

Example: http://lambtonoutdoorclub.org/events/event/port-franks-trails/

The basic code i’m using is:

<?php 

$images = get_field('event_gallery');

if( $images ): ?>
<h3>Event Photos</h3>
    <ul>
        <?php foreach( $images as $image ): ?>
            <li>
                <a href="<?php echo $image['url']; ?>" rel="lightbox[gallery]" title="<?php echo $image['caption']; ?>">
                     <img src="<?php echo $image['sizes']['thumbnail']; ?>" alt="<?php echo $image['alt']; ?>" />
                </a>

            </li>
        <?php endforeach; ?>
    </ul>
<?php endif; ?>

https://wordpress.org/plugins/responsive-lightbox/