Echoing @dhesse90 on this as I, too, am having the same issue after upgrading Woocommerce to 3.4. The main image allows for hover-zoom and Lightbox support when you click the magnifying glass icon, but clicking any of the thumbnail images below does nothing. The images are linked to their source and appropriate URLs are visible in the browser status bar when hovered over, but it’s as if the click event is disabled (as expected) and then the Lightbox trigger never fires.
For testing, I made a copy of the live site to a staging environment, then disabled all plugins except for Woocommerce, and the issue remained. Checked my functions.php and JS files to double-check that there are no conflicts, but nothing jumps out as an issue.
For reference, here’s one of my product pages with the same issue: https://www.theconfettibar.com/shop/unicorn-dandruff/
