diff --git a/core/lib/Drupal/Core/Config/Config.php b/core/lib/Drupal/Core/Config/Config.php
index 52d91fd..6c2e354 100644
--- a/core/lib/Drupal/Core/Config/Config.php
+++ b/core/lib/Drupal/Core/Config/Config.php
@@ -159,7 +159,6 @@ protected function setOverriddenData() {
     }
     if (isset($this->settingsOverrides) && is_array($this->settingsOverrides)) {
       $this->overriddenData = NestedArray::mergeDeepArray(array($this->overriddenData, $this->settingsOverrides), TRUE);
-      $this->overriddenData['isImmutable'] = TRUE;
     }
     return $this;
   }
@@ -286,7 +285,6 @@ public function getOriginal($key = '', $apply_overrides = TRUE) {
       }
       if (isset($this->settingsOverrides) && is_array($this->settingsOverrides)) {
         $original_data = NestedArray::mergeDeepArray(array($original_data, $this->settingsOverrides), TRUE);
-        $original_data['isImmutable'] = TRUE;
       }
     }
 
@@ -305,4 +303,17 @@ public function getOriginal($key = '', $apply_overrides = TRUE) {
     }
   }
 
+  /**
+   * Returns whether this configuration contains any overrides.
+   * 
+   * @return bool
+   *   TRUE if it contains any, FALSE otherwise.
+   */
+  public function containsOverrides() {
+    return (isset($this->overriddenData) || 
+      (isset($this->moduleOverrides) && is_array($this->moduleOverrides)) ||
+      (isset($this->settingsOverrides) && is_array($this->settingsOverrides))        
+    );
+  }
+
 }
diff --git a/core/lib/Drupal/Core/Config/Entity/ConfigEntityStorage.php b/core/lib/Drupal/Core/Config/Entity/ConfigEntityStorage.php
index b6a63b7..800ac9c 100644
--- a/core/lib/Drupal/Core/Config/Entity/ConfigEntityStorage.php
+++ b/core/lib/Drupal/Core/Config/Entity/ConfigEntityStorage.php
@@ -184,7 +184,15 @@ protected function doLoadMultiple(array $ids = NULL) {
     $records = [];
     foreach ($this->configFactory->loadMultiple($names) as $config) {
       $id = $config->get($this->idKey);
-      $records[$id] = $this->overrideFree ? $config->getOriginal(NULL, FALSE) : $config->get();
+      if ($this->overrideFree) {
+        $record = $config->getOriginal(NULL, FALSE);
+      } else {
+        $record = $config->get();
+        if ($config->containsOverrides()) {
+          $record['isImmutable'] = TRUE;
+        }
+      }
+      $records[$id] = $record;
       $configs[$id] = $config;
     }
     $entities = $this->mapFromStorageRecords($records, $configs);
diff --git a/core/tests/Drupal/KernelTests/Core/Config/ConfigEntityOverrideTest.php b/core/tests/Drupal/KernelTests/Core/Config/ConfigEntityOverrideTest.php
index 4a5e2dd..a5d3317 100644
--- a/core/tests/Drupal/KernelTests/Core/Config/ConfigEntityOverrideTest.php
+++ b/core/tests/Drupal/KernelTests/Core/Config/ConfigEntityOverrideTest.php
@@ -83,12 +83,16 @@ function testConfEntityOverride() {
     self::assertSame($config_entity_data['weight'], $expected_original_data['weight']);
 
     // try saving override values
+    $thrown_exception = NULL;
     try {
       /** @var \Drupal\config_test\Entity\ConfigTest $config_entity */
       $config_entity = $config_test_storage->load('dotted.default');
       $config_entity->weight = 240;
       $config_entity->save();
-    } catch (\Exception $e) {}
+    } catch (\Exception $e) {
+      $thrown_exception = $e;
+    }
+    self::assertNotNull($thrown_exception);
 
     // Verify that it contains the overridden data from $config.
     $config_entity = $config_test_storage->load('dotted.default');