diff -u b/core/tests/Drupal/FunctionalJavascriptTests/Core/Render/Element/VerticalTabsTest.php b/core/tests/Drupal/FunctionalJavascriptTests/Core/Render/Element/VerticalTabsTest.php
--- b/core/tests/Drupal/FunctionalJavascriptTests/Core/Render/Element/VerticalTabsTest.php
+++ b/core/tests/Drupal/FunctionalJavascriptTests/Core/Render/Element/VerticalTabsTest.php
@@ -26,7 +26,9 @@
 
     $this->submitForm([], 'Submit');
 
-    $web_assert->elementTextContains('css', '.vertical-tabs__menu-item-title .child-error-indicator', '(contains error)');
+    $title_element = $web_assert->waitForElement('css', '.vertical-tabs__menu-item-title .child-error-indicator');
+
+    $this->assertEquals('(contains error)', $title_element->getText());
   }
 
 }