If we create a gallery of images, link all images and try to open the gallery using the first images we will not be able to do that, but we will be able to open fancybox using the last image in the gallery. The images that didn't open the fancybox will appear in it : https://drive.google.com/file/d/1WCTgVCAmWPTlZQWfXL9pKMDOlSsaROIQ/view
Tested wwith WP 5.6
If we create a gallery of images, link all images and try to open the gallery using the first images we will not be able to do that, but we will be able to open fancybox using the last image in the gallery. The images that didn't open the fancybox will appear in it : https://drive.google.com/file/d/1WCTgVCAmWPTlZQWfXL9pKMDOlSsaROIQ/view
Tested wwith WP 5.6