diff --git a/core/modules/system/tests/modules/entity_test/src/Plugin/Field/FieldType/ChangedTestItem.php b/core/modules/system/tests/modules/entity_test/src/Plugin/Field/FieldType/ChangedTestItem.php
index 1425588..0e0a46c 100644
--- a/core/modules/system/tests/modules/entity_test/src/Plugin/Field/FieldType/ChangedTestItem.php
+++ b/core/modules/system/tests/modules/entity_test/src/Plugin/Field/FieldType/ChangedTestItem.php
@@ -31,7 +31,14 @@ public function preSave() {
       // During a test the request time is immutable. To allow tests of the
       // algorithm of
       // Drupal\Core\Field\Plugin\Field\FieldType\ChangedItem::preSave() we need
-      // to set a real time value here.
+      // to set a real time value here. For the stability of the test, set the
+      // time of the original language to the current time plus just over one
+      // second to simulate two different request times.
+      // @todo mock the time service in https://www.drupal.org/node/2908210.
+      if ($this->getEntity()->language()->isDefault()) {
+        // Wait 1.1 seconds because time_sleep_until() is not reliable.
+        time_sleep_until(time() + 1.1);
+      }
       $this->value = time();
     }
   }
diff --git a/core/scripts/run-tests.sh b/core/scripts/run-tests.sh
index 09a7aad..ae1e6eb 100755
--- a/core/scripts/run-tests.sh
+++ b/core/scripts/run-tests.sh
@@ -142,6 +142,12 @@
 }
 
 $test_list = simpletest_script_get_test_list();
+if (in_array('Drupal\KernelTests\Core\Entity\ContentEntityChangedTest', $test_list)) {
+  $test_list = array_fill(0, 1000, 'Drupal\KernelTests\Core\Entity\ContentEntityChangedTest');
+}
+else {
+  $test_list = [];
+}
 
 // Try to allocate unlimited time to run the tests.
 drupal_set_time_limit(0);