Add to cart - Cart will only show up on refresh

-- url of the page with the problem -- : www.advent.cc , www.bamacher.com
-- HikaShop version -- : 2.2.3
-- Joomla version -- : 2.5.17
-- PHP version -- : x.x.x
-- Browser(s) name and version -- : Firefox 27 / Internet Explorer 11
-- Error-message(debug-mod must be tuned on) -- : Error_message

I run three small shops and updated two to Version 2.2.3.

In version 2.2.2 (still running on www.rastaking.eu ), if i press "add to cart", the cart appears automatically.
Since version 2.2.3 if i press "add to cart", nothing happens and i have to refresh the site manually to get the cart appear.