Was there ever any solution for this? I am having the same problem, I have a product with no images added, with SVI activated it just shows a loading icon instead of the default image. Disabling SVI correctly shows the default image. However, with SVI enabled I noticed in the console there were javascript errors, so I began disabling all other plugins until I found the plugin causing the conflicting javascript errors. With that plugin disabled however, the errors went away from the console but the loading image still shows up, and the javascript still seems to not be working.
With only WooCommerce, SVI, and Redux Framework plugins active I am still just seeing the loading image. Also, I am unable to add anything to the cart without seeing a “Please choose product options…” error even though I am selecting options. This is only happening if I have no images, once I upload them everything works fine.