[Backport 2.1] Issues 6729, 6457, 7362: Configurable product price options provider

Author: simpleadm

app/code/Magento/ConfigurableProduct/Pricing/Price/LowestPriceOptionsProvider.php

@@ -63,7 +63,9 @@ public function getProducts(ProductInterface $product)
             );
 
             $this->productsMap[$product->getId()] = $this->collectionFactory->create()
-                ->addAttributeToSelect(['price', 'special_price'])
+                ->addAttributeToSelect(
+                    ['price', 'special_price', 'special_from_date', 'special_to_date', 'tax_class_id']
+                )
                 ->addIdFilter($productIds)
                 ->getItems();
         }