You have a lot of different effects going on with that page. Image lightbox galleries, videos, etc. all wrapped up in a timeline. So you may want to systematically remove some types of things (e.g. lightbox galleries) and see if that cures the problem. (Of course, it may create another problem: how to handle the lightbox galleries in a different way.)
OTOH I could not replicate what you were say. I had no problems.
… since most of your images on your page are not lightboxed, I’m not sure having a small number lightboxed is going to be an “intuitive” experience for your users. You could add them without the lightbox gallery easy enough. But, again, I’m not experiencing any problems.
… perhaps empty your browser’s cache and try again?