diff --git a/core/modules/layout_builder/src/Normalizer/LayoutEntityDisplayNormalizer.php b/core/modules/layout_builder/src/Normalizer/LayoutEntityDisplayNormalizer.php
index 09e80b430d..209b1dfb97 100644
--- a/core/modules/layout_builder/src/Normalizer/LayoutEntityDisplayNormalizer.php
+++ b/core/modules/layout_builder/src/Normalizer/LayoutEntityDisplayNormalizer.php
@@ -44,7 +44,7 @@ public function hasCacheableSupportsMethod(): bool {
   /**
    * {@inheritdoc}
    */
-  public function denormalize($data, $class, $format = NULL, array $context = []) {
+  public function denormalize($data, $class, $format = NULL, array $context = []): mixed {
     if (!empty($data['third_party_settings']['layout_builder']['sections'])) {
       $sections = &$data['third_party_settings']['layout_builder']['sections'];
       $sections = array_map([Section::class, 'fromArray'], $sections);
diff --git a/core/modules/layout_builder/src/Normalizer/SectionDataNormalizer.php b/core/modules/layout_builder/src/Normalizer/SectionDataNormalizer.php
index bf4a63255a..fcec810ee7 100644
--- a/core/modules/layout_builder/src/Normalizer/SectionDataNormalizer.php
+++ b/core/modules/layout_builder/src/Normalizer/SectionDataNormalizer.php
@@ -28,7 +28,7 @@ public function normalize($object, $format = NULL, array $context = []): array|s
   /**
    * {@inheritdoc}
    */
-  public function denormalize($data, $class, $format = NULL, array $context = []) {
+  public function denormalize($data, $class, $format = NULL, array $context = []): mixed {
     return Section::fromArray((array) $data);
   }