When selecting any value from the drop down of “Default Form Values” in a Variable Product, then on its front-end, it causes only first image to display and all other variation images are hidden. See attached.
On its front-end product page, if user toggles/selects a different variation value (select a different “Product Length”), the other images re-appear magically. Reload the page — the variation images disappear again.
If I change the “Default Form Values” in a Variable Product to “No default Product Length”, then on the front-end all image variations display correctly.
See private area for examples.