I'm working with Magento 18.104.22.168, nginx, mysql and php v 7.1 on Centos 7.6.
Everything works fine except checkout success page. After i try to complete order magento does not redirect to success page and i get the error : *92 FastCGI sent in stderr: "PHP message: PHP Fatal error:
Uncaught TypeError: Argument 1 passed to Mage_Checkout_Block_Cart_Item_Renderer::setItem() must be an instance of Mage_Sales_Model_Quote_Item_Abstract, instance of Mage_Sales_Model_Order_Item given, called in /var/www/html/mysite/app/code/core/Mage/Sales/Block/Items/Abstract.php on line 135 and defined in /var/www/html/mysite/app/code/core/Mage/Checkout/Block/Cart/Item/Renderer.php:65.
Magento shows transactional email template and the url that shows is http:mysite.com/onestepcheckout/index.php/saveOrder. I have uploaded inchoo extension for Magento and Php 7.