klaviyo + shopify back in stock in quickview

We are using the Boost theme from Clean Canvas, and we are trying to integrate Klaviyo's back in stock for the theme. It does work fine for the product-detail-page, but if we try to make it work in the homepage or categories, where multiple products are shown, we get multiple problems

the sold-out button never gets replaced with the notify-me-when-available button

1. I forced the button, adding it to the quick-buy liquid file, but on click the form overlay never pops up. When debugging in the javascript console I see the following error when clicking the button:

 I already read and tested the solutions at

https://community.klaviyo.com/integrations%2D39/back%2Din%2Dstock%2Dbutton%2Dpopup%2Don%2Dshopify%2Dcollection%2Dpages%2D1130

and

Any hints would help.

Thank you.