diff --git a/.github/workflows/documentation.yml b/.github/workflows/documentation.yml
index bd9ebea8d28..ef8053a211c 100644
--- a/.github/workflows/documentation.yml
+++ b/.github/workflows/documentation.yml
@@ -40,5 +40,10 @@ jobs:
         with:
           dependency-versions: "highest"
 
+      - name: "Add orphan metadata where needed"
+        run: |
+          printf '%s\n\n%s\n' ":orphan:" "$(cat docs/en/sidebar.rst)" > docs/en/sidebar.rst
+          printf '%s\n\n%s\n' ":orphan:" "$(cat docs/en/reference/installation.rst)" > docs/en/reference/installation.rst
+
       - name: "Run guides-cli"
         run: "vendor/bin/guides -vvv --no-progress docs/en 2>&1 | grep -v 'No template found for rendering directive' | ( ! grep WARNING )"
diff --git a/docs/en/reference/installation.rst b/docs/en/reference/installation.rst
index 2c0d5823009..dab1364f777 100644
--- a/docs/en/reference/installation.rst
+++ b/docs/en/reference/installation.rst
@@ -1,5 +1,3 @@
-:orphan:
-
 Installation
 ============
 
diff --git a/docs/en/sidebar.rst b/docs/en/sidebar.rst
index 619c6e2511a..db7da890ac9 100644
--- a/docs/en/sidebar.rst
+++ b/docs/en/sidebar.rst
@@ -1,5 +1,3 @@
-:orphan:
-
 .. toc::
 
    .. tocheader:: Tutorials
diff --git a/src/UnitOfWork.php b/src/UnitOfWork.php
index e1336140640..4577ccb6648 100644
--- a/src/UnitOfWork.php
+++ b/src/UnitOfWork.php
@@ -2662,7 +2662,19 @@ private function eagerLoadCollections(array $collections, ToManyInverseSideMappi
             foreach ($found as $targetValue) {
                 $sourceEntity = $targetProperty->getValue($targetValue);
 
-                $id     = $this->identifierFlattener->flattenIdentifier($class, $class->getIdentifierValues($sourceEntity));
+                if ($sourceEntity === null && isset($targetClass->associationMappings[$mappedBy]['joinColumns'])) {
+                    // case where the hydration $targetValue itself has not yet fully completed, for example
+                    // in case a bi-directional association is being hydrated and deferring eager loading is
+                    // not possible due to subclassing.
+                    $data = $this->getOriginalEntityData($targetValue);
+                    $id   = [];
+                    foreach ($targetClass->associationMappings[$mappedBy]['joinColumns'] as $joinColumn) {
+                        $id[] = $data[$joinColumn['name']];
+                    }
+                } else {
+                    $id = $this->identifierFlattener->flattenIdentifier($class, $class->getIdentifierValues($sourceEntity));
+                }
+
                 $idHash = implode(' ', $id);
 
                 if ($mapping->indexBy !== null) {
diff --git a/tests/Tests/Models/AbstractFetchEager/AbstractRemoteControl.php b/tests/Tests/Models/AbstractFetchEager/AbstractRemoteControl.php
new file mode 100644
index 00000000000..6ef67359e99
--- /dev/null
+++ b/tests/Tests/Models/AbstractFetchEager/AbstractRemoteControl.php
@@ -0,0 +1,35 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Doctrine\Tests\Models\AbstractFetchEager;
+
+use Doctrine\Common\Collections\ArrayCollection;
+use Doctrine\Common\Collections\Collection;
+use Doctrine\ORM\Mapping as ORM;
+
+#[ORM\Entity]
+#[ORM\Table(name: 'abstract_fetch_eager_remote_control')]
+#[ORM\InheritanceType('SINGLE_TABLE')]
+#[ORM\DiscriminatorColumn(name: 'type', type: 'string')]
+#[ORM\DiscriminatorMap(['mobile' => 'MobileRemoteControl'])]
+abstract class AbstractRemoteControl
+{
+    #[ORM\Id]
+    #[ORM\GeneratedValue]
+    #[ORM\Column(type: 'integer')]
+    public int $id;
+
+    #[ORM\Column(type: 'string')]
+    public string $name;
+
+    /** @var Collection<User> */
+    #[ORM\OneToMany(targetEntity: User::class, mappedBy: 'remoteControl', fetch: 'EAGER')]
+    public Collection $users;
+
+    public function __construct(string $name)
+    {
+        $this->name  = $name;
+        $this->users = new ArrayCollection();
+    }
+}
diff --git a/tests/Tests/Models/AbstractFetchEager/MobileRemoteControl.php b/tests/Tests/Models/AbstractFetchEager/MobileRemoteControl.php
new file mode 100644
index 00000000000..c9246036741
--- /dev/null
+++ b/tests/Tests/Models/AbstractFetchEager/MobileRemoteControl.php
@@ -0,0 +1,12 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Doctrine\Tests\Models\AbstractFetchEager;
+
+use Doctrine\ORM\Mapping as ORM;
+
+#[ORM\Entity]
+class MobileRemoteControl extends AbstractRemoteControl
+{
+}
diff --git a/tests/Tests/Models/AbstractFetchEager/User.php b/tests/Tests/Models/AbstractFetchEager/User.php
new file mode 100644
index 00000000000..5755c359514
--- /dev/null
+++ b/tests/Tests/Models/AbstractFetchEager/User.php
@@ -0,0 +1,26 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Doctrine\Tests\Models\AbstractFetchEager;
+
+use Doctrine\ORM\Mapping as ORM;
+
+#[ORM\Entity]
+#[ORM\Table(name: 'abstract_fetch_eager_user')]
+class User
+{
+    #[ORM\Id]
+    #[ORM\GeneratedValue]
+    #[ORM\Column(type: 'integer')]
+    public int $id;
+
+    #[ORM\ManyToOne(targetEntity: AbstractRemoteControl::class, inversedBy: 'users')]
+    #[ORM\JoinColumn(nullable: false)]
+    public AbstractRemoteControl $remoteControl;
+
+    public function __construct(AbstractRemoteControl $control)
+    {
+        $this->remoteControl = $control;
+    }
+}
diff --git a/tests/Tests/ORM/Functional/AbstractFetchEagerTest.php b/tests/Tests/ORM/Functional/AbstractFetchEagerTest.php
new file mode 100644
index 00000000000..c8166c3d03d
--- /dev/null
+++ b/tests/Tests/ORM/Functional/AbstractFetchEagerTest.php
@@ -0,0 +1,37 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Doctrine\Tests\ORM\Functional;
+
+use Doctrine\Tests\Models\AbstractFetchEager\AbstractRemoteControl;
+use Doctrine\Tests\Models\AbstractFetchEager\MobileRemoteControl;
+use Doctrine\Tests\Models\AbstractFetchEager\User;
+use Doctrine\Tests\OrmFunctionalTestCase;
+
+final class AbstractFetchEagerTest extends OrmFunctionalTestCase
+{
+    public function testWithAbstractFetchEager(): void
+    {
+        $this->createSchemaForModels(
+            AbstractRemoteControl::class,
+            User::class,
+        );
+
+        $control = new MobileRemoteControl('smart');
+        $user    = new User($control);
+
+        $entityManage = $this->getEntityManager();
+
+        $entityManage->persist($control);
+        $entityManage->persist($user);
+        $entityManage->flush();
+        $entityManage->clear();
+
+        $user = $entityManage->find(User::class, $user->id);
+
+        self::assertNotNull($user);
+        self::assertEquals('smart', $user->remoteControl->name);
+        self::assertTrue($user->remoteControl->users->contains($user));
+    }
+}