Add to cart button keeps circling after clicking on it

The add to cart button keeps circling after user clicks on it in the following website. Can anyone advise and help?

https://tiramizus-de-sensare.com/

@Tiramizus

Where exactly does it happen? It seems to work fine with the following product.

https://tiramizus-de-sensare.com/collections/tiramizu/products/tiramizus