diff --git a/src/Resolvers/TransformedDataResolver.php b/src/Resolvers/TransformedDataResolver.php
index d615e976d..0e28f233a 100644
--- a/src/Resolvers/TransformedDataResolver.php
+++ b/src/Resolvers/TransformedDataResolver.php
@@ -59,7 +59,7 @@ private function transform(BaseData&TransformableData $data, TransformationConte
                     return $payload;
                 }
 
-                if ($property->type->isOptional && ! isset($data->{$name})) {
+                if ($property->type->isOptional && ! array_key_exists($name, get_object_vars($data))) {
                     return $payload;
                 }
 
diff --git a/tests/DataCollectionTest.php b/tests/DataCollectionTest.php
index 4f807860a..67d0071a7 100644
--- a/tests/DataCollectionTest.php
+++ b/tests/DataCollectionTest.php
@@ -80,7 +80,7 @@
 });
 
 test('a collection can be rejected', function () {
-    $collection = SimpleData::collection(['A', 'B']);
+    $collection = new DataCollection(SimpleData::class, ['A', 'B']);
 
     $filtered = $collection->reject(fn (SimpleData $data) => $data->string === 'B')->toArray();