diff --git a/core/modules/node/lib/Drupal/node/Form/NodeRevisionDeleteForm.php b/core/modules/node/lib/Drupal/node/Form/NodeRevisionDeleteForm.php
index 14244c5..60a929c 100644
--- a/core/modules/node/lib/Drupal/node/Form/NodeRevisionDeleteForm.php
+++ b/core/modules/node/lib/Drupal/node/Form/NodeRevisionDeleteForm.php
@@ -79,7 +79,7 @@ public static function create(ContainerInterface $container) {
    * {@inheritdoc}
    */
   public function getFormID() {
-    return 'node.revision_delete_confirm';
+    return 'node_revision_delete_confirm';
   }
 
   /**
diff --git a/core/modules/system/lib/Drupal/system/Form/PerformanceForm.php b/core/modules/system/lib/Drupal/system/Form/PerformanceForm.php
index 3d30c10..92404b7 100644
--- a/core/modules/system/lib/Drupal/system/Form/PerformanceForm.php
+++ b/core/modules/system/lib/Drupal/system/Form/PerformanceForm.php
@@ -55,7 +55,7 @@ public static function create(ContainerInterface $container) {
    * {@inheritdoc}
    */
   public function getFormID() {
-    return 'system.performance_settings';
+    return 'system_performance_settings';
   }
 
   /**
diff --git a/core/modules/system/lib/Drupal/system/Form/SiteMaintenanceModeForm.php b/core/modules/system/lib/Drupal/system/Form/SiteMaintenanceModeForm.php
index bcb0f8f..e83b93f 100644
--- a/core/modules/system/lib/Drupal/system/Form/SiteMaintenanceModeForm.php
+++ b/core/modules/system/lib/Drupal/system/Form/SiteMaintenanceModeForm.php
@@ -55,7 +55,7 @@ public static function create(ContainerInterface $container) {
    * {@inheritdoc}
    */
   public function getFormID() {
-    return 'system.site_maintenance_mode';
+    return 'system_site_maintenance_mode';
   }
 
   /**