Hello, @Estudio EntreDos,
The issue you are facing is because of you had not used the attributes created under Products >> Attributes for your products, but instead, you used the Custom Attributes and that is the reason, the theme setting is not working on the Custom Attributes.
I have checked your products, lets’s example this one: https://www.clovetpetit.com/producto/camisa-jardin-frances/
I have edited that particular product and find that you are using the Custom Attribute for it: https://postimg.cc/F1rQ4YBS
Then I went to Products >> Attributes and find that you have only one attribute named “Talla” and all the variations under it are not assigned to any of the products as shown in this screenshot: https://postimg.cc/SXSwp5Zh
Then I created a test product and then assigned those variations to that product and it is working fine, you can check it here: https://www.clovetpetit.com/producto/test-product/
After checking please delete that test product as its only for testing/confirmation purposes.
Regards 8Themes Team.