diff --git a/src/JsonSchema/SchemaFactory.php b/src/JsonSchema/SchemaFactory.php
index d6253f28e8d..097eaddd4b8 100644
--- a/src/JsonSchema/SchemaFactory.php
+++ b/src/JsonSchema/SchemaFactory.php
@@ -160,6 +160,11 @@ private function buildPropertySchema(Schema $schema, string $definitionName, str
             $additionalPropertySchema ?? []
         );
 
+        // @see https://github.com/api-platform/core/issues/6299
+        if (Schema::UNKNOWN_TYPE === ($propertySchema['type'] ?? null) && isset($propertySchema['$ref'])) {
+            unset($propertySchema['type']);
+        }
+
         $extraProperties = $propertyMetadata->getExtraProperties() ?? [];
         // see AttributePropertyMetadataFactory
         if (true === ($extraProperties[SchemaPropertyMetadataFactory::JSON_SCHEMA_USER_DEFINED] ?? false)) {
diff --git a/src/Symfony/Messenger/ContextStamp.php b/src/Symfony/Messenger/ContextStamp.php
index 98e2570b4e1..6723b17c47f 100644
--- a/src/Symfony/Messenger/ContextStamp.php
+++ b/src/Symfony/Messenger/ContextStamp.php
@@ -13,6 +13,7 @@
 
 namespace ApiPlatform\Symfony\Messenger;
 
+use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\Messenger\Stamp\StampInterface;
 
 /**
@@ -22,8 +23,15 @@
  */
 final class ContextStamp implements StampInterface
 {
-    public function __construct(private readonly array $context = [])
+    private readonly array $context;
+
+    public function __construct(array $context = [])
     {
+        if (($request = ($context['request'] ?? null)) && $request instanceof Request && $request->hasSession()) {
+            unset($context['request']);
+        }
+
+        $this->context = $context;
     }
 
     /**
diff --git a/tests/Fixtures/TestBundle/ApiResource/Issue6299/Issue6299.php b/tests/Fixtures/TestBundle/ApiResource/Issue6299/Issue6299.php
new file mode 100644
index 00000000000..35c4f08dbd5
--- /dev/null
+++ b/tests/Fixtures/TestBundle/ApiResource/Issue6299/Issue6299.php
@@ -0,0 +1,23 @@
+<?php
+
+/*
+ * This file is part of the API Platform project.
+ *
+ * (c) Kévin Dunglas <dunglas@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace ApiPlatform\Tests\Fixtures\TestBundle\ApiResource\Issue6299;
+
+use ApiPlatform\Metadata\ApiResource;
+use ApiPlatform\Metadata\Get;
+
+#[ApiResource]
+#[Get(output: Issue6299OutputDto::class)]
+final class Issue6299
+{
+}
diff --git a/tests/Fixtures/TestBundle/ApiResource/Issue6299/Issue6299CollectionDto.php b/tests/Fixtures/TestBundle/ApiResource/Issue6299/Issue6299CollectionDto.php
new file mode 100644
index 00000000000..5e9791d11a3
--- /dev/null
+++ b/tests/Fixtures/TestBundle/ApiResource/Issue6299/Issue6299CollectionDto.php
@@ -0,0 +1,19 @@
+<?php
+
+/*
+ * This file is part of the API Platform project.
+ *
+ * (c) Kévin Dunglas <dunglas@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace ApiPlatform\Tests\Fixtures\TestBundle\ApiResource\Issue6299;
+
+final class Issue6299CollectionDto
+{
+    public string $name;
+}
diff --git a/tests/Fixtures/TestBundle/ApiResource/Issue6299/Issue6299ItemDto.php b/tests/Fixtures/TestBundle/ApiResource/Issue6299/Issue6299ItemDto.php
new file mode 100644
index 00000000000..4f06aaca373
--- /dev/null
+++ b/tests/Fixtures/TestBundle/ApiResource/Issue6299/Issue6299ItemDto.php
@@ -0,0 +1,19 @@
+<?php
+
+/*
+ * This file is part of the API Platform project.
+ *
+ * (c) Kévin Dunglas <dunglas@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace ApiPlatform\Tests\Fixtures\TestBundle\ApiResource\Issue6299;
+
+final class Issue6299ItemDto
+{
+    public string $name;
+}
diff --git a/tests/Fixtures/TestBundle/ApiResource/Issue6299/Issue6299OutputDto.php b/tests/Fixtures/TestBundle/ApiResource/Issue6299/Issue6299OutputDto.php
new file mode 100644
index 00000000000..51687855872
--- /dev/null
+++ b/tests/Fixtures/TestBundle/ApiResource/Issue6299/Issue6299OutputDto.php
@@ -0,0 +1,39 @@
+<?php
+
+/*
+ * This file is part of the API Platform project.
+ *
+ * (c) Kévin Dunglas <dunglas@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace ApiPlatform\Tests\Fixtures\TestBundle\ApiResource\Issue6299;
+
+use ApiPlatform\Metadata\ApiProperty;
+use Symfony\Component\Serializer\Attribute\Groups;
+
+final class Issue6299OutputDto
+{
+    #[ApiProperty(
+        openapiContext: ['$ref' => '#/components/schemas/DummyFriend'],
+        jsonSchemaContext: ['$ref' => '#/definitions/DummyFriend'],
+    )]
+    #[Groups(['v1.read', 'v2.read'])]
+    public Issue6299ItemDto $itemDto;
+
+    #[ApiProperty(
+        openapiContext: [
+            'items' => ['$ref' => '#/components/schemas/DummyDate'],
+        ],
+        jsonSchemaContext: [
+            'items' => ['$ref' => '#/definitions/DummyDate'],
+        ],
+    )]
+    #[Groups(['v1.read', 'v2.read'])]
+    /** @var Issue6299CollectionDto[] */
+    public array $collectionDto;
+}
diff --git a/tests/JsonSchema/Command/JsonSchemaGenerateCommandTest.php b/tests/JsonSchema/Command/JsonSchemaGenerateCommandTest.php
index 11a38ed1b63..b7c33c76555 100644
--- a/tests/JsonSchema/Command/JsonSchemaGenerateCommandTest.php
+++ b/tests/JsonSchema/Command/JsonSchemaGenerateCommandTest.php
@@ -166,6 +166,19 @@ public function testWritableNonResourceRef(): void
         $this->assertEquals($json['definitions']['SaveProduct.jsonld']['properties']['codes']['items']['$ref'], '#/definitions/ProductCode.jsonld');
     }
 
+    /**
+     * Test issue #6299.
+     */
+    public function testOpenApiResourceRefIsNotOverwritten(): void
+    {
+        $this->tester->run(['command' => 'api:json-schema:generate', 'resource' => 'ApiPlatform\Tests\Fixtures\TestBundle\ApiResource\Issue6299\Issue6299', '--type' => 'output']);
+        $result = $this->tester->getDisplay();
+        $json = json_decode($result, associative: true);
+
+        $this->assertEquals('#/definitions/DummyFriend', $json['definitions']['Issue6299.Issue6299OutputDto.jsonld']['properties']['itemDto']['$ref']);
+        $this->assertEquals('#/definitions/DummyDate', $json['definitions']['Issue6299.Issue6299OutputDto.jsonld']['properties']['collectionDto']['items']['$ref']);
+    }
+
     /**
      * Test related Schema keeps json-ld context.
      */
diff --git a/tests/Symfony/Messenger/ContextStampTest.php b/tests/Symfony/Messenger/ContextStampTest.php
index 9de929c7297..db185821785 100644
--- a/tests/Symfony/Messenger/ContextStampTest.php
+++ b/tests/Symfony/Messenger/ContextStampTest.php
@@ -15,6 +15,7 @@
 
 use ApiPlatform\Symfony\Messenger\ContextStamp;
 use PHPUnit\Framework\TestCase;
+use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\Messenger\Stamp\StampInterface;
 
 /**
@@ -32,4 +33,16 @@ public function testGetContext(): void
         $contextStamp = new ContextStamp();
         $this->assertIsArray($contextStamp->getContext());
     }
+
+    /**
+     * @doesNotPerformAssertions
+     */
+    public function testSerializable(): void
+    {
+        $request = new Request();
+        $request->setSessionFactory(function (): void {}); // @phpstan-ignore-line
+
+        $stamp = new ContextStamp(['request' => $request]);
+        serialize($stamp);
+    }
 }