Categories listing not showing sub categories

-- HikaShop version -- : latest
-- Joomla version -- : 3.3.6
-- PHP version -- : latest
-- Browser(s) name and version -- : Chrome

Hi,

I'm trying to set a Categories listing which used to work fine but after I've moved one sub category to a different location it stopped showing my sub categories and just shows a blank page.

I've set the menu item to "Categories listing" and under "HikaShop Options" selected my main category "Products". Checked that it is published and in "Parameter for categories" made sure it's set to "Show sub categories" -> "All sub categories". Still, the sub categories are not shown.

When I check the URL provided under "Menu" in Hikashop I can see the subcategories just fine:
gurtech.guywalderonline.com/index.php?op...egory&layout=listing

The site MUST go live this week and I would REALLY like to solve this issue asap.

Update:
I guess it's some sort of a bug as I've tried to create a new menu item without going into "HikaShop Options" and it worked. It automatically took the root products and shows all sub categories.

Best regards,

Guy.