diff --git a/core/modules/block/lib/Drupal/block/BlockBase.php b/core/modules/block/lib/Drupal/block/BlockBase.php
index f057f0a..69d7e66 100644
--- a/core/modules/block/lib/Drupal/block/BlockBase.php
+++ b/core/modules/block/lib/Drupal/block/BlockBase.php
@@ -52,8 +52,6 @@ public function getConfig() {
       // If the plugin configuration is not already set, initialize it with the
       // default settings for the block plugin.
       $this->configuration = $this->blockSettings();
-      // Ensure that the default cache mode is set.
-      $this->configuration += array('cache' => DRUPAL_NO_CACHE);
 
       // @todo This loads the default subject. Is this the right place to do so?
       $definition = $this->getDefinition();
@@ -61,6 +59,8 @@ public function getConfig() {
         $this->configuration += array('subject' => $definition['subject']);
       }
     }
+    // Ensure that the default cache mode is set.
+    $this->configuration += array('cache' => DRUPAL_NO_CACHE);
     return $this->configuration;
   }
 
diff --git a/core/modules/block/lib/Drupal/block/Plugin/Core/Entity/Block.php b/core/modules/block/lib/Drupal/block/Plugin/Core/Entity/Block.php
index 7996c93..415d43b 100644
--- a/core/modules/block/lib/Drupal/block/Plugin/Core/Entity/Block.php
+++ b/core/modules/block/lib/Drupal/block/Plugin/Core/Entity/Block.php
@@ -149,12 +149,11 @@ public function getPlugin() {
    */
   public function get($property_name, $langcode = NULL) {
     // The theme is stored in the entity ID.
-    if ($property_name == 'theme') {
-      list($theme) = explode('.', $this->id());
-      return $theme;
+    $value = parent::get($property_name, $langcode);
+    if ($property_name == 'theme' && !$value) {
+      list($value) = explode('.', $this->id());
     }
-
-    return parent::get($property_name, $langcode);
+    return $value;
   }
 
   /**