diff --git a/core/modules/system/src/Form/ModulesListForm.php b/core/modules/system/src/Form/ModulesListForm.php
index d0ec6f5b036fba4bc32b590d5eadb12042b44df4..8df4971db03206ce97cb4ff250381fd0483bf775 100644
--- a/core/modules/system/src/Form/ModulesListForm.php
+++ b/core/modules/system/src/Form/ModulesListForm.php
@@ -263,7 +263,7 @@ protected function buildRow(array $modules, Extension $module, $distribution) {
           Url::fromUri($module->info[ExtensionLifecycle::LIFECYCLE_LINK_IDENTIFIER], [
             'attributes' =>
               [
-                'class' => 'module-link--non-stable',
+                'class' => ['module-link--non-stable'],
                 'aria-label' => $this->t('View information on the @lifecycle status of the module @module', [
                   '@lifecycle' => ucfirst($lifecycle),
                   '@module' => $module->info['name'],