Hi,
As I said, if it's not a view override issue, it's probably an issue with the settings of your menu item.
You say it's a plugin but it's not. The plugin displays the menu items in the menu, but when you click on one of these menu items, it's the menu item with the alias "hikashop-menu-for-categories-listing" which is used.
So you need to check its settings via the Joomla menu manager.
And similarly for your new menu item, one of its settings must be a problem.
For example, if you have the "discount only" setting activated in them but you don't have any products with a discount, then the products listing would be empty.