Multiple product forms fix

If the product options are not saved when adding a product to the cart, then it might be the case that your theme is using multiple product forms on the product page and the app is attached to the wrong form.

Automatic

On most themes, the issue can be resolved by adding the app block via the theme editor as described here: Product Options Block in Theme Editor

Manual

Some themes overwrite the product form id even with the app block configured, in this case it's requires to add the data-product-form attribute to the right product form:

{%- capture form_product_id -%}{{ product.id }}{%- endcapture -%}
{%- form 'product', product, id: form_id, data-product-form: form_product_id -%}