REST API problem

Hello
The problem is that plugin (popupbuilder-woocommerce) adds/echos script tag on woocommerce_add_to_cart action and when it is done via REST Api it breaks the response.

File: popupbuilder-woocommerce\com\classes\Filters.php
Function:
add_action('woocommerce_add_to_cart', array($this, 'addToCartNotAjax'));

public function addToCartNotAjax()
{
$cartArgs = array(
'total-price' => GetProductsHelper::getTotalPrice(),
'number-of-product' => GetProductsHelper::getNumberOfProducts(),
'products-ids' => GetProductsHelper::getProductsIds()
);
$cartArgs = json_encode($cartArgs);
$redirectAfterAddToCart = get_option('woocommerce_cart_redirect_after_add');
if (!defined('DOING_AJAX') && $redirectAfterAddToCart == 'no') {
echo "SCRIPT HERE";
}
}

screenshot
https://freeimage.host/i/HUwc10N

Is it possible to add REST Api check or add a filter so that echoing can be disabled on demand?
Thanks