I understand it may seem odd at first, but this is by design for performance.
The AJAX Products Tabs scripts are initialized by the products element that is present on initial page load. Only the first tab’s products are rendered in the DOM when the page loads; the other tabs load their content via AJAX later. If the first tab returns no products, there is no products element to trigger the initialization, so image-related scripts aren’t started and images in other tabs won’t appear.
This approach prevents loading and running those scripts globally on every page, which would negatively affect performance. To avoid the issue, make sure the first tab always has products (or place a populated tab first) so the scripts can initialize when the page loads.
.
