CMS Page "Link to other lightboxes" not working


I have a CMS page with multiple lightboxes in the collection list, pulling images from a CMS multi-image field. By default, “Link to other lightboxes” was working. I unchecked it, published it, re-checked, and it’s not working. I’ve searched around, does anyone know how to solve this issue?

Here is my site Read-Only: LINK
(how to share your site Read-Only link)