diff -u b/core/lib/Drupal/Core/Config/BatchConfigImporter.php b/core/lib/Drupal/Core/Config/BatchConfigImporter.php
--- b/core/lib/Drupal/Core/Config/BatchConfigImporter.php
+++ b/core/lib/Drupal/Core/Config/BatchConfigImporter.php
@@ -70,7 +70,7 @@
   }
 
   /**
-   * Processes batch.
+   * Processes extensions as a batch operation.
    *
    * @param array $context.
    *   The batch context.
@@ -89,6 +89,12 @@
     }
   }
 
+  /**
+   * Processes configuration as a batch operation.
+   *
+   * @param array $context.
+   *   The batch context.
+   */
   public function processConfigurationBatch(array &$context) {
     // The first time this is called we need to calculate the total to process.
     // This involves recalculating the changelist which will ensure that if
@@ -112,6 +118,12 @@
     }
   }
 
+  /**
+   * Finishes the batch.
+   *
+   * @param array $context.
+   *   The batch context.
+   */
   public function finishBatch(array &$context) {
     $this->eventDispatcher->dispatch(ConfigEvents::IMPORT, new ConfigImporterEvent($this));
     // The import is now complete.
diff -u b/core/lib/Drupal/Core/Config/ConfigImporter.php b/core/lib/Drupal/Core/Config/ConfigImporter.php
--- b/core/lib/Drupal/Core/Config/ConfigImporter.php
+++ b/core/lib/Drupal/Core/Config/ConfigImporter.php
@@ -480,9 +480,10 @@
       // Installing a module can cause a kernel boot therefore reinject all the
       // services.
       $this->reInjectMe();
-      // During the container is rebuilt and the module handler is called from
-      // drupal_get_complete_schema(). This causes the container's instance of
-      // the module handler not to have loaded.
+      // During a module install or uninstall the container is rebuilt and the
+      // module handler is called from drupal_get_complete_schema(). This causes
+      // the container's instance of the module handler not to have loaded all
+      // the enabled modules.
       $this->moduleHandler->loadAll();
     }
     if ($type == 'theme') {