Hi,
I have added the following code in the file "components/com_hikashop/views/checkout/view.html.php" in the "notice()" function:
JRequest::setVar('cart_type',JRequest::getVar('cart_type',''));
And this code in the view "checkout / notice":
$cart_type = JRequest::getVar('cart_type','');
if(empty($cart_type))
$cart_type = $app->getUserState( HIKASHOP_COMPONENT.'.popup_cart_type','cart');
Instead of that one:
$cart_type = $app->getUserState( HIKASHOP_COMPONENT.'.popup_cart_type','cart');
This allow to get the cart type from parameters and not from the session, I tried it on your website and this seems to be working as expected.
Please confirm that this fix solve your issue.