Hi,
I have had a look today to see whats causing the error, I have tracked it down to com_hikashop/views/product/view.html.php If I edit out the lines below then the page displays correctly. If the lines are left in the product is displayed at the top of the page and then the 404 not found is displayed below. I use ACL on different categories and products and without the lines below it appears to work correctly.
595 if(!count($pageInfo->filter->cid)) {
596 throw new Exception(JText::_('CATEGORY_NOT_FOUND'), 404);
597 }
The version i was using last was 4.0.3 and have commented out the above lines in 4.2.0
Category not found
/var/www/vhosts/example.com/components/com_hikashop/views/product/view.html.php:596
Call stack
# Function Location
1 () JROOT/components/com_hikashop/views/product/view.html.php:596
2 ProductViewProduct->listing() JROOT/components/com_hikashop/views/product/view.html.php:28
3 ProductViewProduct->display() JROOT/administrator/components/com_hikashop/helpers/helper.php:766
4 hikashop_getLayout() JROOT/modules/mod_hikashop/mod_hikashop.php:73
5 include() JROOT/plugins/system/t3/includes/joomla4/ModuleHelper.php:201
6 Joomla\CMS\Helper\ModuleHelper::renderModule() JROOT/components/com_hikashop/views/product/tmpl/show.php:391
7 include() JROOT/libraries/src/MVC/View/HtmlView.php:697
8 Joomla\CMS\MVC\View\HtmlView->loadTemplate() JROOT/administrator/components/com_hikashop/helpers/helper.php:2263
9 hikashopView->loadTemplate() JROOT/libraries/src/MVC/View/HtmlView.php:230
10 Joomla\CMS\MVC\View\HtmlView->display() JROOT/administrator/components/com_hikashop/helpers/helper.php:2246
11 hikashopView->display() JROOT/components/com_hikashop/views/product/view.html.php:29
12 ProductViewProduct->display() JROOT/libraries/src/MVC/Controller/BaseController.php:672
13 Joomla\CMS\MVC\Controller\BaseController->display() JROOT/administrator/components/com_hikashop/helpers/helper.php:1984
14 hikashopController->display() JROOT/administrator/components/com_hikashop/helpers/helper.php:1725
15 hikashopController->show() JROOT/libraries/src/MVC/Controller/BaseController.php:710
16 Joomla\CMS\MVC\Controller\BaseController->execute() JROOT/administrator/components/com_hikashop/helpers/helper.php:1962
17 hikashopController->execute() JROOT/components/com_hikashop/hikashop.php:92
18 require_once() JROOT/libraries/src/Component/ComponentHelper.php:402
19 Joomla\CMS\Component\ComponentHelper::executeComponent() JROOT/libraries/src/Component/ComponentHelper.php:377
20 Joomla\CMS\Component\ComponentHelper::renderComponent() JROOT/libraries/src/Application/SiteApplication.php:194
21 Joomla\CMS\Application\SiteApplication->dispatch() JROOT/libraries/src/Application/SiteApplication.php:233
22 Joomla\CMS\Application\SiteApplication->doExecute() JROOT/libraries/src/Application/CMSApplication.php:196
23 Joomla\CMS\Application\CMSApplication->execute() JROOT/index.php:49