So I have identified the issue but I can’t fix it right now. If I fix it, it breaks the compatibility with variable products…
I have contacted WooCommerce to see if they can slightly change their plugin in order to fix this, I hope they will.
In the meantime, I guess it is ok for you to use dropdowns or radio buttons. I had never tested this image option, it’s pretty cool. I really hope I can make it work in the future.
In the meanwhile, we will use dropdowns as you suggested, I hope that WooCommerce fixes the problem. Unfortunately, it is not the first time that we have problems with Product Addons 🙁 they sometimes do weird undocumented things in updates… 😉