diff --git a/core/lib/Drupal/Core/Block/BlockBase.php b/core/lib/Drupal/Core/Block/BlockBase.php
index 9963132..66f6cb3 100644
--- a/core/lib/Drupal/Core/Block/BlockBase.php
+++ b/core/lib/Drupal/Core/Block/BlockBase.php
@@ -163,8 +163,7 @@ protected function blockAccess(AccountInterface $account) {
    */
   public function buildConfigurationForm(array $form, FormStateInterface $form_state) {
     $definition = $this->getPluginDefinition();
-    $temporary = $form_state->getTemporary();
-    $contexts = isset($temporary['gathered_contexts']) ? $temporary['gathered_contexts'] : [];
+    $contexts = $form_state->getTemporaryValue('gathered_contexts') ?: [];
     $form['context_mapping'] = $this->addContextAssignmentElement($this, $contexts);
     $form['provider'] = array(
       '#type' => 'value',
diff --git a/core/modules/aggregator/src/Entity/Feed.php b/core/modules/aggregator/src/Entity/Feed.php
index 6532f36..6125e16 100644
--- a/core/modules/aggregator/src/Entity/Feed.php
+++ b/core/modules/aggregator/src/Entity/Feed.php
@@ -114,9 +114,13 @@ public static function postDelete(EntityStorageInterface $storage, array $entiti
     parent::postDelete($storage, $entities);
     if (\Drupal::moduleHandler()->moduleExists('block')) {
       // Make sure there are no active blocks for these feeds.
+      $context_ids = array_keys($entities);
+      foreach ($context_ids as $key => $value) {
+        $context_ids[$key] = 'aggregator.feed:' . $value;
+      }
       $ids = \Drupal::entityQuery('block')
         ->condition('plugin', 'aggregator_feed_block')
-        ->condition('settings.feed', array_keys($entities))
+        ->condition('settings.context_mapping.feed', $context_ids)
         ->execute();
       if ($ids) {
         $block_storage = \Drupal::entityManager()->getStorage('block');