No error reporting when a product is out of stock and payment page type is "Lightbox"

[roadster31]

When the "Pay" button is clicked, if one of the products in the cart is out of stock, and the "payment page type" setting is set to "lightbox", the user is not redirected to the cart page, the loading indicator keeps turning indefinitely.

Under the hood, an exception is thrown : No route found for "GET /order/undefined" (from "http://localhost/thelia2/index_dev.php/order/invoice")

The stack trace is not really useful.

Everything is OK if the "payment page type" is set to "Hosted Page"