diff --git a/core/modules/layout_builder/src/Form/AddBlockForm.php b/core/modules/layout_builder/src/Form/AddBlockForm.php
index 14d9646f9e..704d136ba9 100644
--- a/core/modules/layout_builder/src/Form/AddBlockForm.php
+++ b/core/modules/layout_builder/src/Form/AddBlockForm.php
@@ -47,8 +47,12 @@ protected function submitLabel() {
    *   The form array.
    */
   public function buildForm(array $form, FormStateInterface $form_state, SectionStorageInterface $section_storage = NULL, $delta = NULL, $region = NULL, $plugin_id = NULL) {
-    $component = new SectionComponent($this->uuidGenerator->generate(), $region, ['id' => $plugin_id]);
-    $section_storage->getSection($delta)->appendComponent($component);
+    // Only generate a new component once per form submission.
+    if (!$component = $form_state->getTemporaryValue('layout_builder__component')) {
+      $component = new SectionComponent($this->uuidGenerator->generate(), $region, ['id' => $plugin_id]);
+      $section_storage->getSection($delta)->appendComponent($component);
+      $form_state->setTemporaryValue('layout_builder__component', $component);
+    }
     return $this->doBuildForm($form, $form_state, $section_storage, $delta, $component);
   }