please have a look at the following page.
In the first section with a single element "Tour" the lightbox works if you click on one of the thumbnails.
In the second section with 2 elements "Tour" does not work on the second button "Content 2" the lightbox.
The picture is only opened on the same page.
I have tried it with different picture galleries, names, and also with "TAB" and "Akkordion".
The first button works always, but others unfortunately not.
Please take a look at this.