Hi,
When you click on the checkout button, the Itemid of the url is transfered to the next page so that you can keep all your modules which are displayed on the current page.
You can either:
1/ not display the cart module on the front page.
2/ change the code of the cart file of the view product in Display->Views in order to not transfer the Itemid in the url of the checkout button. Note that if you do so , you will have to change the code
$view->setLayout($layout);
to
$folder = JPATH_BASE.DS.'templates'.DS.$app->getTemplate().DS.'html'.DS.HIKASHOP_COMPONENT.DS.$view->getName();
$view->addTemplatePath($folder);
$view->setLayout($layout);
in the function getLayout of the file administrator/components/com_hikashop/helpers/helper.php near line 380
That is to fix another problem that we found yesterday where the modified version of the cart view would not be used by joomla.