diff --git a/src/Mapper/Proxy/Hydrator/ClosureHydrator.php b/src/Mapper/Proxy/Hydrator/ClosureHydrator.php
index cf24767d..55061f65 100644
--- a/src/Mapper/Proxy/Hydrator/ClosureHydrator.php
+++ b/src/Mapper/Proxy/Hydrator/ClosureHydrator.php
@@ -83,56 +83,60 @@ private function setEntityProperties(array $properties, object $object, array &$
     }
 
     /**
-     * Map private entity relations
+     * Map private relations of non-proxy entity
      */
     private function setRelationProperties(array $properties, RelationMap $relMap, object $object, array &$data): void
     {
         $refl = new \ReflectionClass($object);
+        $setter = static function (object $object, array $props, array &$data) use ($refl, $relMap): void {
+            foreach ($props as $property) {
+                if (!\array_key_exists($property, $data)) {
+                    continue;
+                }
 
-        foreach ($properties as $class => $props) {
-            if ($class === '') {
-                continue;
-            }
-
-            Closure::bind(static function (object $object, array $props, array &$data) use ($refl, $relMap): void {
-                foreach ($props as $property) {
-                    if (!\array_key_exists($property, $data)) {
-                        continue;
-                    }
-
-                    $value = $data[$property];
+                $value = $data[$property];
 
-                    if ($value instanceof ReferenceInterface) {
-                        $prop = $refl->getProperty($property);
+                if ($value instanceof ReferenceInterface) {
+                    $prop = $refl->getProperty($property);
 
-                        if ($prop->hasType()) {
-                            /** @var \ReflectionNamedType[] $types */
-                            $types = $prop->getType() instanceof \ReflectionUnionType
-                                ? $prop->getType()->getTypes()
-                                : [$prop->getType()];
+                    if ($prop->hasType()) {
+                        // todo: we can cache this
+                        /** @var \ReflectionNamedType[] $types */
+                        $types = $prop->getType() instanceof \ReflectionUnionType
+                            ? $prop->getType()->getTypes()
+                            : [$prop->getType()];
 
-                            foreach ($types as $type) {
-                                $c = $type->getName();
-                                if ($c === 'object' || $value instanceof $c) {
-                                    $object->{$property} = $value;
-                                    unset($data[$property]);
+                        foreach ($types as $type) {
+                            $c = $type->getName();
+                            if ($c === 'object' || $value instanceof $c) {
+                                $object->{$property} = $value;
+                                unset($data[$property]);
 
-                                    // go to next property
-                                    continue 2;
-                                }
+                                // go to next property
+                                continue 2;
                             }
+                        }
 
-                            $relation = $relMap->getRelations()[$property] ?? null;
-                            if ($relation !== null) {
-                                $value = $relation->collect($relation->resolve($value, true));
-                            }
+                        $relation = $relMap->getRelations()[$property] ?? null;
+                        if ($relation !== null) {
+                            $value = $relation->collect($relation->resolve($value, true));
                         }
                     }
-
-                    $object->{$property} = $value;
-                    unset($data[$property]);
                 }
-            }, null, $class)($object, $props, $data);
+
+                $object->{$property} = $value;
+                unset($data[$property]);
+            }
+        };
+
+        foreach ($properties as $class => $props) {
+            if ($class === '') {
+                // Hydrate public properties
+                $setter($object, $props, $data);
+                continue;
+            }
+
+            Closure::bind($setter, null, $class)($object, $props, $data);
         }
     }
 }
diff --git a/src/Mapper/StdMapper.php b/src/Mapper/StdMapper.php
index 9f985ead..896c683e 100644
--- a/src/Mapper/StdMapper.php
+++ b/src/Mapper/StdMapper.php
@@ -21,7 +21,7 @@ public function hydrate($entity, array $data): object
     {
         $relations = $this->relationMap->getRelations();
         foreach ($data as $k => $v) {
-            if ($v instanceof ReferenceInterface && array_key_exists($k, $relations)) {
+            if ($v instanceof ReferenceInterface && \array_key_exists($k, $relations)) {
                 $relation = $relations[$k];
                 $relation->resolve($v, false);
 
diff --git a/tests/ORM/Functional/Driver/Common/Integration/Case416/CaseTest.php b/tests/ORM/Functional/Driver/Common/Integration/Case416/CaseTest.php
new file mode 100644
index 00000000..90e966b8
--- /dev/null
+++ b/tests/ORM/Functional/Driver/Common/Integration/Case416/CaseTest.php
@@ -0,0 +1,100 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Cycle\ORM\Tests\Functional\Driver\Common\Integration\Case416;
+
+use Cycle\ORM\Select;
+use Cycle\ORM\Tests\Functional\Driver\Common\BaseTest;
+use Cycle\ORM\Tests\Functional\Driver\Common\Integration\IntegrationTestTrait;
+use Cycle\ORM\Tests\Traits\TableTrait;
+use Ramsey\Uuid\Uuid;
+
+abstract class CaseTest extends BaseTest
+{
+    use IntegrationTestTrait;
+    use TableTrait;
+
+    public function setUp(): void
+    {
+        // Init DB
+        parent::setUp();
+        $this->makeTables();
+
+        $this->loadSchema(__DIR__ . '/schema.php');
+    }
+
+    public function testSelect(): void
+    {
+        $uuid = Uuid::uuid7();
+        $identity = new Entity\Identity($uuid);
+        $profile = new Entity\Profile($uuid);
+        $account = new Entity\Account($uuid, 'test@mail.com', \md5('password'));
+        $identity->profile = $profile;
+        $identity->account = $account;
+
+        $this->save($identity);
+
+        // Note: heap cleaning fixes this issue
+        // $this->orm->getHeap()->clean();
+
+        // Get entity
+        (new Select($this->orm, Entity\Account::class))
+            ->load('identity.profile')
+            ->wherePK((string)$uuid)
+            ->fetchOne();
+
+        // There is no any exception like this:
+        // [Cycle\ORM\Exception\MapperException]
+        // Can't hydrate an entity because property and value types are incompatible.
+        //
+        // [TypeError]
+        // Cannot assign Cycle\ORM\Reference\Reference to property
+        // Cycle\ORM\Tests\Functional\Driver\Common\Integration\Case416\Entity\Profile::$identity of type
+        // Cycle\ORM\Tests\Functional\Driver\Common\Integration\Case416\Entity\Identity
+        $this->assertTrue(true);
+
+        // To avoid `Entity and State are not in sync` exception
+        $this->orm->getHeap()->clean();
+    }
+
+    private function makeTables(): void
+    {
+        $this->makeTable(Entity\Identity::ROLE, [
+            'uuid' => 'string,primary',
+            'created_at' => 'datetime',
+            'updated_at' => 'datetime',
+            'deleted_at' => 'datetime,nullable',
+        ]);
+
+        $this->makeTable(Entity\Account::ROLE, [
+            'uuid' => 'string,primary',
+            'email' => 'string',
+            'password_hash' => 'string',
+            'updated_at' => 'datetime',
+        ]);
+        $this->makeFK(
+            Entity\Account::ROLE,
+            'uuid',
+            Entity\Identity::ROLE,
+            'uuid',
+            'NO ACTION',
+            'NO ACTION',
+        );
+
+        $this->makeTable(Entity\Profile::ROLE, [
+            'uuid' => 'string,primary',
+            'updated_at' => 'datetime',
+            'first_name' => 'string',
+            'last_name' => 'string',
+        ]);
+        $this->makeFK(
+            Entity\Profile::ROLE,
+            'uuid',
+            Entity\Identity::ROLE,
+            'uuid',
+            'NO ACTION',
+            'NO ACTION',
+        );
+    }
+}
diff --git a/tests/ORM/Functional/Driver/Common/Integration/Case416/Entity/Account.php b/tests/ORM/Functional/Driver/Common/Integration/Case416/Entity/Account.php
new file mode 100644
index 00000000..6a4b8496
--- /dev/null
+++ b/tests/ORM/Functional/Driver/Common/Integration/Case416/Entity/Account.php
@@ -0,0 +1,32 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Cycle\ORM\Tests\Functional\Driver\Common\Integration\Case416\Entity;
+
+use DateTimeInterface;
+use Ramsey\Uuid\UuidInterface;
+
+class Account
+{
+    public const ROLE = 'account';
+
+    public const F_UUID = 'uuid';
+    public const F_EMAIL = 'email';
+    public const F_PASSWORD_HASH = 'passwordHash';
+    public const F_UPDATED_AT = 'updatedAt';
+
+    /** @readonly */
+    public DateTimeInterface $updatedAt;
+
+    public Identity $identity;
+
+    public function __construct(
+        /** @readonly */
+        public UuidInterface $uuid,
+        public string $email,
+        public string $passwordHash,
+    ) {
+        $this->updatedAt = new \DateTimeImmutable();
+    }
+}
diff --git a/tests/ORM/Functional/Driver/Common/Integration/Case416/Entity/Identity.php b/tests/ORM/Functional/Driver/Common/Integration/Case416/Entity/Identity.php
new file mode 100644
index 00000000..36c831ff
--- /dev/null
+++ b/tests/ORM/Functional/Driver/Common/Integration/Case416/Entity/Identity.php
@@ -0,0 +1,38 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Cycle\ORM\Tests\Functional\Driver\Common\Integration\Case416\Entity;
+
+use DateTimeInterface;
+use Ramsey\Uuid\UuidInterface;
+
+class Identity
+{
+    public const ROLE = 'identity';
+
+    public const F_UUID = 'uuid';
+    public const F_CREATED_AT = 'createdAt';
+    public const F_UPDATED_AT = 'updatedAt';
+    public const F_DELETED_AT = 'deletedAt';
+
+    /** @readonly */
+    public DateTimeInterface $createdAt;
+    /** @readonly */
+    public DateTimeInterface $updatedAt;
+    /** @readonly */
+    public ?DateTimeInterface $deletedAt = null;
+
+    public Profile $profile;
+
+    public Account $account;
+
+    public function __construct(
+        /** @readonly */
+        public UuidInterface $uuid,
+    ) {
+        $now = new \DateTimeImmutable();
+        $this->createdAt = $now;
+        $this->updatedAt = $now;
+    }
+}
diff --git a/tests/ORM/Functional/Driver/Common/Integration/Case416/Entity/Profile.php b/tests/ORM/Functional/Driver/Common/Integration/Case416/Entity/Profile.php
new file mode 100644
index 00000000..b758b6ac
--- /dev/null
+++ b/tests/ORM/Functional/Driver/Common/Integration/Case416/Entity/Profile.php
@@ -0,0 +1,32 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Cycle\ORM\Tests\Functional\Driver\Common\Integration\Case416\Entity;
+
+use DateTimeInterface;
+use Ramsey\Uuid\UuidInterface;
+
+class Profile
+{
+    public const ROLE = 'profile';
+
+    public const F_UUID = 'uuid';
+    public const F_UPDATED_AT = 'updatedAt';
+
+    /** @readonly */
+    public DateTimeInterface $updatedAt;
+
+    /** @psalm-suppress InvalidArgument */
+    public UserName $name;
+
+    public Identity $identity;
+
+    public function __construct(
+        /** @readonly */
+        public UuidInterface $uuid,
+    ) {
+        $this->name = new UserName();
+        $this->updatedAt = new \DateTimeImmutable();
+    }
+}
diff --git a/tests/ORM/Functional/Driver/Common/Integration/Case416/Entity/UserName.php b/tests/ORM/Functional/Driver/Common/Integration/Case416/Entity/UserName.php
new file mode 100644
index 00000000..c9755cde
--- /dev/null
+++ b/tests/ORM/Functional/Driver/Common/Integration/Case416/Entity/UserName.php
@@ -0,0 +1,19 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Cycle\ORM\Tests\Functional\Driver\Common\Integration\Case416\Entity;
+
+class UserName
+{
+    public const ROLE = 'UserName';
+
+    public const F_FIRST_NAME = 'firstName';
+    public const F_LAST_NAME = 'lastName';
+
+    public function __construct(
+        public string $firstName = '',
+        public string $lastName = '',
+    ) {
+    }
+}
diff --git a/tests/ORM/Functional/Driver/Common/Integration/Case416/Typecast/UuidTypecast.php b/tests/ORM/Functional/Driver/Common/Integration/Case416/Typecast/UuidTypecast.php
new file mode 100644
index 00000000..2ecfc62e
--- /dev/null
+++ b/tests/ORM/Functional/Driver/Common/Integration/Case416/Typecast/UuidTypecast.php
@@ -0,0 +1,59 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Cycle\ORM\Tests\Functional\Driver\Common\Integration\Case416\Typecast;
+
+use Cycle\ORM\Parser\CastableInterface;
+use Cycle\ORM\Parser\UncastableInterface;
+use Ramsey\Uuid\Uuid;
+use Ramsey\Uuid\UuidInterface;
+
+class UuidTypecast implements CastableInterface, UncastableInterface
+{
+    /** @var non-empty-string[] */
+    private array $rules = [];
+
+    public function setRules(array $rules): array
+    {
+        /**
+         * @var non-empty-string $key
+         * @var mixed $rule
+         */
+        foreach ($rules as $key => $rule) {
+            if ($rule === 'uuid') {
+                unset($rules[$key]);
+                $this->rules[$key] = $rule;
+            }
+        }
+
+        return $rules;
+    }
+
+    public function cast(array $data): array
+    {
+        foreach ($this->rules as $column => $rule) {
+            if (!isset($data[$column])) {
+                continue;
+            }
+
+            \assert(\is_string($data[$column]));
+            $data[$column] = Uuid::fromString($data[$column]);
+        }
+
+        return $data;
+    }
+
+    public function uncast(array $data): array
+    {
+        foreach ($this->rules as $column => $rule) {
+            if (!isset($data[$column]) || !$data[$column] instanceof UuidInterface) {
+                continue;
+            }
+
+            $data[$column] = $data[$column]->toString();
+        }
+
+        return $data;
+    }
+}
diff --git a/tests/ORM/Functional/Driver/Common/Integration/Case416/schema.php b/tests/ORM/Functional/Driver/Common/Integration/Case416/schema.php
new file mode 100644
index 00000000..49024c51
--- /dev/null
+++ b/tests/ORM/Functional/Driver/Common/Integration/Case416/schema.php
@@ -0,0 +1,161 @@
+<?php
+
+declare(strict_types=1);
+
+use Cycle\ORM\Relation;
+use Cycle\ORM\SchemaInterface as Schema;
+use Cycle\ORM\Tests\Functional\Driver\Common\Integration\Case416\Entity\Account;
+use Cycle\ORM\Tests\Functional\Driver\Common\Integration\Case416\Entity\Identity;
+use Cycle\ORM\Tests\Functional\Driver\Common\Integration\Case416\Entity\Profile;
+use Cycle\ORM\Tests\Functional\Driver\Common\Integration\Case416\Entity\UserName;
+use Cycle\ORM\Tests\Functional\Driver\Common\Integration\Case416\Typecast\UuidTypecast;
+
+return [
+    'account' => [
+        Schema::ENTITY => Account::class,
+        Schema::MAPPER => Cycle\ORM\Mapper\Mapper::class,
+        Schema::SOURCE => Cycle\ORM\Select\Source::class,
+        Schema::DATABASE => 'default',
+        Schema::TABLE => 'account',
+        Schema::PRIMARY_KEY => ['uuid'],
+        Schema::FIND_BY_KEYS => ['uuid'],
+        Schema::COLUMNS => [
+            'uuid' => 'uuid',
+            'email' => 'email',
+            'passwordHash' => 'password_hash',
+            'updatedAt' => 'updated_at',
+        ],
+        Schema::RELATIONS => [
+            'identity' => [
+                Relation::TYPE => Relation::BELONGS_TO,
+                Relation::TARGET => 'identity',
+                Relation::LOAD => Relation::LOAD_PROMISE,
+                Relation::SCHEMA => [
+                    Relation::CASCADE => true,
+                    Relation::NULLABLE => false,
+                    Relation::INNER_KEY => ['uuid'],
+                    Relation::OUTER_KEY => ['uuid'],
+                    Relation::INVERSION => 'account',
+                ],
+            ],
+        ],
+        Schema::SCOPE => null,
+        Schema::TYPECAST => [
+            'uuid' => 'uuid',
+            'updatedAt' => 'datetime',
+        ],
+        Schema::SCHEMA => [],
+        Schema::TYPECAST_HANDLER => [UuidTypecast::class, Cycle\ORM\Parser\Typecast::class],
+    ],
+    'identity' => [
+        Schema::ENTITY => Identity::class,
+        Schema::MAPPER => Cycle\ORM\Mapper\Mapper::class,
+        Schema::SOURCE => Cycle\ORM\Select\Source::class,
+        Schema::DATABASE => 'default',
+        Schema::TABLE => 'identity',
+        Schema::PRIMARY_KEY => ['uuid'],
+        Schema::FIND_BY_KEYS => ['uuid'],
+        Schema::COLUMNS => [
+            'uuid' => 'uuid',
+            'createdAt' => 'created_at',
+            'updatedAt' => 'updated_at',
+            'deletedAt' => 'deleted_at',
+        ],
+        Schema::RELATIONS => [
+            'profile' => [
+                Relation::TYPE => Relation::HAS_ONE,
+                Relation::TARGET => 'profile',
+                Relation::LOAD => Relation::LOAD_PROMISE,
+                Relation::SCHEMA => [
+                    Relation::CASCADE => true,
+                    Relation::NULLABLE => false,
+                    Relation::INNER_KEY => ['uuid'],
+                    Relation::OUTER_KEY => ['uuid'],
+                    Relation::INVERSION => 'identity',
+                ],
+            ],
+            'account' => [
+                Relation::TYPE => Relation::HAS_ONE,
+                Relation::TARGET => 'account',
+                Relation::LOAD => Relation::LOAD_PROMISE,
+                Relation::SCHEMA => [
+                    Relation::CASCADE => true,
+                    Relation::NULLABLE => false,
+                    Relation::INNER_KEY => ['uuid'],
+                    Relation::OUTER_KEY => ['uuid'],
+                    Relation::INVERSION => 'identity',
+                ],
+            ],
+        ],
+        Schema::SCOPE => null,
+        Schema::TYPECAST => [
+            'uuid' => 'uuid',
+            'createdAt' => 'datetime',
+            'updatedAt' => 'datetime',
+            'deletedAt' => 'datetime',
+        ],
+        Schema::SCHEMA => [],
+        Schema::TYPECAST_HANDLER => [UuidTypecast::class, Cycle\ORM\Parser\Typecast::class],
+    ],
+    'profile' => [
+        Schema::ENTITY => Profile::class,
+        Schema::MAPPER => Cycle\ORM\Mapper\Mapper::class,
+        Schema::SOURCE => Cycle\ORM\Select\Source::class,
+        Schema::DATABASE => 'default',
+        Schema::TABLE => 'profile',
+        Schema::PRIMARY_KEY => ['uuid'],
+        Schema::FIND_BY_KEYS => ['uuid'],
+        Schema::COLUMNS => [
+            'uuid' => 'uuid',
+            'updatedAt' => 'updated_at',
+        ],
+        Schema::RELATIONS => [
+            'name' => [
+                Relation::TYPE => 1,
+                Relation::TARGET => 'profile:userName:name',
+                Relation::LOAD => Relation::LOAD_EAGER,
+                Relation::SCHEMA => [],
+            ],
+            'identity' => [
+                Relation::TYPE => Relation::BELONGS_TO,
+                Relation::TARGET => 'identity',
+                Relation::LOAD => Relation::LOAD_PROMISE,
+                Relation::SCHEMA => [
+                    Relation::CASCADE => true,
+                    Relation::NULLABLE => false,
+                    Relation::INNER_KEY => ['uuid'],
+                    Relation::OUTER_KEY => ['uuid'],
+                    Relation::INVERSION => 'profile',
+                ],
+            ],
+        ],
+        Schema::SCOPE => null,
+        Schema::TYPECAST => [
+            'uuid' => 'uuid',
+            'updatedAt' => 'datetime',
+        ],
+        Schema::SCHEMA => [],
+        Schema::TYPECAST_HANDLER => [UuidTypecast::class, Cycle\ORM\Parser\Typecast::class],
+    ],
+    'profile:userName:name' => [
+        Schema::ENTITY => UserName::class,
+        Schema::MAPPER => Cycle\ORM\Mapper\Mapper::class,
+        Schema::SOURCE => Cycle\ORM\Select\Source::class,
+        Schema::DATABASE => 'default',
+        Schema::TABLE => 'profile',
+        Schema::PRIMARY_KEY => ['uuid'],
+        Schema::FIND_BY_KEYS => ['uuid'],
+        Schema::COLUMNS => [
+            'firstName' => 'first_name',
+            'lastName' => 'last_name',
+            'uuid' => 'uuid',
+        ],
+        Schema::RELATIONS => [],
+        Schema::SCOPE => null,
+        Schema::TYPECAST => [
+            'uuid' => 'uuid',
+        ],
+        Schema::SCHEMA => [],
+        Schema::TYPECAST_HANDLER => [UuidTypecast::class, Cycle\ORM\Parser\Typecast::class],
+    ],
+];
diff --git a/tests/ORM/Functional/Driver/MySQL/Integration/Case416/CaseTest.php b/tests/ORM/Functional/Driver/MySQL/Integration/Case416/CaseTest.php
new file mode 100644
index 00000000..7b9a5c66
--- /dev/null
+++ b/tests/ORM/Functional/Driver/MySQL/Integration/Case416/CaseTest.php
@@ -0,0 +1,17 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Cycle\ORM\Tests\Functional\Driver\MySQL\Integration\Case416;
+
+// phpcs:ignore
+use Cycle\ORM\Tests\Functional\Driver\Common\Integration\Case416\CaseTest as CommonClass;
+
+/**
+ * @group driver
+ * @group driver-mysql
+ */
+class CaseTest extends CommonClass
+{
+    public const DRIVER = 'mysql';
+}
diff --git a/tests/ORM/Functional/Driver/Postgres/Integration/Case416/CaseTest.php b/tests/ORM/Functional/Driver/Postgres/Integration/Case416/CaseTest.php
new file mode 100644
index 00000000..85b51096
--- /dev/null
+++ b/tests/ORM/Functional/Driver/Postgres/Integration/Case416/CaseTest.php
@@ -0,0 +1,17 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Cycle\ORM\Tests\Functional\Driver\Postgres\Integration\Case416;
+
+// phpcs:ignore
+use Cycle\ORM\Tests\Functional\Driver\Common\Integration\Case416\CaseTest as CommonClass;
+
+/**
+ * @group driver
+ * @group driver-postgres
+ */
+class CaseTest extends CommonClass
+{
+    public const DRIVER = 'postgres';
+}
diff --git a/tests/ORM/Functional/Driver/SQLServer/Integration/Case416/CaseTest.php b/tests/ORM/Functional/Driver/SQLServer/Integration/Case416/CaseTest.php
new file mode 100644
index 00000000..ebbe50a0
--- /dev/null
+++ b/tests/ORM/Functional/Driver/SQLServer/Integration/Case416/CaseTest.php
@@ -0,0 +1,17 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Cycle\ORM\Tests\Functional\Driver\SQLServer\Integration\Case416;
+
+// phpcs:ignore
+use Cycle\ORM\Tests\Functional\Driver\Common\Integration\Case416\CaseTest as CommonClass;
+
+/**
+ * @group driver
+ * @group driver-sqlserver
+ */
+class CaseTest extends CommonClass
+{
+    public const DRIVER = 'sqlserver';
+}
diff --git a/tests/ORM/Functional/Driver/SQLite/Integration/Case416/CaseTest.php b/tests/ORM/Functional/Driver/SQLite/Integration/Case416/CaseTest.php
new file mode 100644
index 00000000..2e68cfc7
--- /dev/null
+++ b/tests/ORM/Functional/Driver/SQLite/Integration/Case416/CaseTest.php
@@ -0,0 +1,17 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Cycle\ORM\Tests\Functional\Driver\SQLite\Integration\Case416;
+
+// phpcs:ignore
+use Cycle\ORM\Tests\Functional\Driver\Common\Integration\Case416\CaseTest as CommonClass;
+
+/**
+ * @group driver
+ * @group driver-sqlite
+ */
+class CaseTest extends CommonClass
+{
+    public const DRIVER = 'sqlite';
+}