Fatal Error on both front- and backend

Following error crashes both Gutenberg editor and Elementor Gallery in frontend.

Fatal error: Uncaught Error: array_keys(): Argument #1 ($array) must be of type array, null given
in?/var/www/vhosts/leader.lu/httpdocs/web/wp-content/plugins/navz-photo-gallery/includes/acf_photo_gallery.php?on line?26

I fixed it by adding following condition :

if ( $meta_data['sizes'] && is_array($meta_data['sizes']) ) {
  foreach (array_keys($meta_data['sizes']) as $size) {
    $meta_data['sizes'][$size]['source_url'] = wp_get_attachment_image_url($image->ID, $size);
  }
}

It only happened on one post for me. Gallery contains 2 JPG images. Please let me know if you want me to enquire further.

I’d like to help improve this plugin because I think it is pretty damn cool.