Thanks for sharing your question with the Klaviyo Community!
Since it actually looks like your button is also using a Class notation, I would recommend, instead of using the ID installation method, to be using the alternate installation method as detailed in the Alternate Code Snippet for "Add to Cart" Button with Class Notation subsection of the How to Create a Custom "Added to Cart" Event for Shopify article. In fact, it appears that the Class used for your button within your Shopify theme is the exact example highlighted in this alternate installation method in the help article.
I would also suggest taking a look at some similar Community posts on this same topic which can be found below:
Thanks for sharing your question with the Klaviyo Community!
Since it actually looks like your button is also using a Class notation, I would recommend, instead of using the ID installation method, to be using the alternate installation method as detailed in the Alternate Code Snippet for "Add to Cart" Button with Class Notation subsection of the How to Create a Custom "Added to Cart" Event for Shopify article. In fact, it appears that the Class used for your button within your Shopify theme is the exact example highlighted in this alternate installation method in the help article.
I would also suggest taking a look at some similar Community posts on this same topic which can be found below: