diff --git a/Source/CesiumRuntime/Private/Tests/CesiumPropertyTable.spec.cpp b/Source/CesiumRuntime/Private/Tests/CesiumPropertyTable.spec.cpp
index c1cf7cc34..d04e56a61 100644
--- a/Source/CesiumRuntime/Private/Tests/CesiumPropertyTable.spec.cpp
+++ b/Source/CesiumRuntime/Private/Tests/CesiumPropertyTable.spec.cpp
@@ -24,7 +24,7 @@ void FCesiumPropertyTableSpec::Define() {
     model = CesiumGltf::Model();
     pExtension =
         &model.addExtension<CesiumGltf::ExtensionModelExtStructuralMetadata>();
-    pExtension->schema = CesiumGltf::Schema();
+    pExtension->schema.emplace();
     pPropertyTable = &pExtension->propertyTables.emplace_back();
   });
 
@@ -44,7 +44,7 @@ void FCesiumPropertyTableSpec::Define() {
     });
 
     It("constructs invalid instance for missing schema", [this]() {
-      pExtension->schema = std::nullopt;
+      pExtension->schema.reset();
 
       FCesiumPropertyTable propertyTable(model, *pPropertyTable);
       TestEqual(
diff --git a/Source/CesiumRuntime/Private/Tests/CesiumPropertyTexture.spec.cpp b/Source/CesiumRuntime/Private/Tests/CesiumPropertyTexture.spec.cpp
index 623959fbe..8465832f7 100644
--- a/Source/CesiumRuntime/Private/Tests/CesiumPropertyTexture.spec.cpp
+++ b/Source/CesiumRuntime/Private/Tests/CesiumPropertyTexture.spec.cpp
@@ -36,7 +36,7 @@ void FCesiumPropertyTextureSpec::Define() {
   BeforeEach([this]() {
     model = Model();
     pExtension = &model.addExtension<ExtensionModelExtStructuralMetadata>();
-    pExtension->schema = Schema();
+    pExtension->schema.emplace();
     pPropertyTexture = &pExtension->propertyTextures.emplace_back();
   });
 
@@ -55,7 +55,7 @@ void FCesiumPropertyTextureSpec::Define() {
     });
 
     It("constructs invalid instance for missing schema", [this]() {
-      pExtension->schema = std::nullopt;
+      pExtension->schema.reset();
 
       FCesiumPropertyTexture propertyTexture(model, *pPropertyTexture);
       TestEqual(
diff --git a/extern/cesium-native b/extern/cesium-native
index 651d3b4d4..a52b11448 160000
--- a/extern/cesium-native
+++ b/extern/cesium-native
@@ -1 +1 @@
-Subproject commit 651d3b4d4309343f9fca725393777752c8ba98c5
+Subproject commit a52b11448cb72c3c17e6fe591f74fbcb8e9daa9c