diff --git a/CHANGELOG.md b/CHANGELOG.md
index 27144d1..be1253b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -12,6 +12,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Fixed
 - [GH#184](https://github.com/jolicode/automapper/pull/184) Fix error when mapping from stdClass to constructor with nullable/optional arguments
 - [GH#185](https://github.com/jolicode/automapper/pull/185) Fix constructor with default parameter array does not work with constructor_arguments context
+- [GH#187](https://github.com/jolicode/automapper/pull/187) Fix regression after [GH#184](https://github.com/jolicode/automapper/pull/184)
 
 ## [9.1.2] - 2024-09-03
 ### Fixed
diff --git a/src/Transformer/NullableTransformer.php b/src/Transformer/NullableTransformer.php
index 10a8b50..f770be6 100644
--- a/src/Transformer/NullableTransformer.php
+++ b/src/Transformer/NullableTransformer.php
@@ -11,7 +11,7 @@
 use PhpParser\Node\Stmt;
 
 /**
- * Tansformer decorator to handle null values.
+ * Transformer decorator to handle null values.
  *
  * @author Joel Wurtz <jwurtz@jolicode.com>
  *
@@ -51,9 +51,9 @@ public function transform(Expr $input, Expr $target, PropertyMetadata $propertyM
             $itemStatements[] = new Stmt\Expression(new $assignClass($newOutput, $output));
         }
 
-        if ($input instanceof Expr\ArrayDimFetch) {
+        if ($propertyMapping->source->checkExists) {
             /*
-             * if `$input` is an array access, let's validate if the array key exists and is not null:
+             * if `$input` is an array access or stdClass, let's validate if the key exists and is not null:
              *
              * if (isset($value['key'])) {
              */
diff --git a/src/Transformer/NullableTransformerFactory.php b/src/Transformer/NullableTransformerFactory.php
index bf48a57..13450c1 100644
--- a/src/Transformer/NullableTransformerFactory.php
+++ b/src/Transformer/NullableTransformerFactory.php
@@ -21,10 +21,6 @@ final class NullableTransformerFactory implements TransformerFactoryInterface, P
 
     public function getTransformer(TypesMatching $types, SourcePropertyMetadata $source, TargetPropertyMetadata $target, MapperMetadata $mapperMetadata): ?TransformerInterface
     {
-        if (null !== $target->parameterInConstructor) {
-            return null;
-        }
-
         $sourceType = $types->getSourceUniqueType();
 
         if (null === $sourceType) {
diff --git a/tests/Fixtures/ConstructorWithDefaultValues.php b/tests/Fixtures/ConstructorWithDefaultValues.php
index 9912837..4383ff9 100644
--- a/tests/Fixtures/ConstructorWithDefaultValues.php
+++ b/tests/Fixtures/ConstructorWithDefaultValues.php
@@ -11,6 +11,7 @@ public function __construct(
         public ?int $foo = 1,
         public int $bar = 0,
         public array $someOtters = [],
+        public ?IntDTO $nullableObject = null,
     ) {
     }
 }