Hi Laranz,
yes. it was my fault to. But nothing happend in the end :).
I think the issue has something to do with yith wishlist premium. When you are logged in, the wishlist is working perfect (thanks for integration!!!), the little popup opens. But when you are logged out, the little wishlist ajax cart is not functioning correct. There are no products in the little ajax cart, but the product is added to the wichlist. You can try it by yourself, when you are logged out.
You can find the staging site in hidden content ;)…