Two Lightboxes Display When Photo Clicked

When I create a gallery and select a view for “Lightbox”, two light boxes appear to show.

If you visit the page below, and click on an image, you will see that it opens up into a lightbox view. If you click to the side of the image to close that lightbox, you will see another one shows behind it as well:

Screenshot 1 (first lightbox that shows): https://i.imgur.com/99sFr6O.jpg

Screenshot 2 (second lightbox):https://i.imgur.com/FsNXlAp.jpg

Site: https://runningriddles.com/races/marathon/the-2017-run-for-the-ranch-marathon-in-springfield-missouri/

I am not running any other lightbox plugins.

The page I need help with: [log in to see the link]