Hello,
In case the product does not have the second image, the image does not change. If there is a blank item appears, check the product, perhaps this blank item is uploaded as an image in the product.
Please provide the site admin access to the private area as well as page URL with the problem.
If it not possible to disable this option for one product and leave for another. This option is disabled in the Theme Settings > Shop
Please check your plugin with Storefront theme. Our theme does not influence the Woocommerce functionality.
Best Regards