Thumbnails not working on touch screens

Hello – Very nice plugin, but I’m having the same problem identified here: https://www.ads-software.com/support/topic/thumbnails-on-smartphones-no-action/

On a laptop, when I click on a thumbnail, it goes to that image & displays it full-size. That works fine. However, on an ipad, when I tap a thumbnail, it doesn’t go to the full-size image. The full-size image doesn’t change; it just stays on the original image.

In the row of thumbnails, it ends up with 2 thumbnails being highlighted with the color selected in ‘Thumbnail Options’ > ‘Border color in hover and active’: the original image + the one I’ve just tapped. But it doesn’t actually display the one I just tapped.

The site is not live yet, so I cannot share a link. I’ve switched temporarily to Twenty Sixteen theme, but I still have the problem.

Thank you