diff --git a/tests/Doctrine/Tests/Models/Issue9300/Issue9300Child.php b/tests/Doctrine/Tests/Models/Issue9300/Issue9300Child.php
new file mode 100644
index 00000000000..eb22eb04ace
--- /dev/null
+++ b/tests/Doctrine/Tests/Models/Issue9300/Issue9300Child.php
@@ -0,0 +1,44 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Doctrine\Tests\Models\Issue9300;
+
+use Doctrine\Common\Collections\ArrayCollection;
+use Doctrine\Common\Collections\Collection;
+use Doctrine\ORM\Mapping\Column;
+use Doctrine\ORM\Mapping\Entity;
+use Doctrine\ORM\Mapping\GeneratedValue;
+use Doctrine\ORM\Mapping\Id;
+use Doctrine\ORM\Mapping\ManyToMany;
+
+/**
+ * @Entity
+ */
+class Issue9300Child
+{
+    /**
+     * @var int
+     * @Id
+     * @Column(type="integer")
+     * @GeneratedValue
+     */
+    public $id;
+
+    /**
+     * @var Collection|Issue9300Parent
+     * @ManyToMany(targetEntity="Issue9300Parent")
+     */
+    public $parents;
+
+    /**
+     * @var string
+     * @Column(type="string")
+     */
+    public $name;
+
+    public function __construct()
+    {
+        $this->parents = new ArrayCollection();
+    }
+}
diff --git a/tests/Doctrine/Tests/Models/Issue9300/Issue9300Parent.php b/tests/Doctrine/Tests/Models/Issue9300/Issue9300Parent.php
new file mode 100644
index 00000000000..73dc28df1ce
--- /dev/null
+++ b/tests/Doctrine/Tests/Models/Issue9300/Issue9300Parent.php
@@ -0,0 +1,31 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Doctrine\Tests\Models\Issue9300;
+
+use Doctrine\ORM\Mapping\Column;
+use Doctrine\ORM\Mapping\Entity;
+use Doctrine\ORM\Mapping\GeneratedValue;
+use Doctrine\ORM\Mapping\Id;
+
+/**
+ * @Entity
+ */
+class Issue9300Parent
+{
+
+    /**
+     * @var int
+     * @Id
+     * @Column(type="integer")
+     * @GeneratedValue
+     */
+    public $id;
+
+    /**
+     * @var string
+     * @Column(type="string")
+     */
+    public $name;
+}
diff --git a/tests/Doctrine/Tests/ORM/Functional/Ticket/Issue9300Test.php b/tests/Doctrine/Tests/ORM/Functional/Ticket/Issue9300Test.php
new file mode 100644
index 00000000000..bdef383380d
--- /dev/null
+++ b/tests/Doctrine/Tests/ORM/Functional/Ticket/Issue9300Test.php
@@ -0,0 +1,79 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Doctrine\Tests\ORM\Functional\Ticket;
+
+use Doctrine\Common\Collections\ArrayCollection;
+use Doctrine\Tests\Models\Issue9300\Issue9300Child;
+use Doctrine\Tests\Models\Issue9300\Issue9300Parent;
+use Doctrine\Tests\OrmFunctionalTestCase;
+
+/**
+ * @group 9300
+ */
+class Issue9300Test extends OrmFunctionalTestCase
+{
+    protected function setUp(): void
+    {
+        $this->useModelSet('issue9300');
+        parent::setUp();
+    }
+
+    /**
+     * @group #9300
+     */
+    public function testPersistedCollectionIsPresentInOriginalDataAfterFlush(): void
+    {
+        $parent = new Issue9300Parent();
+        $child  = new Issue9300Child();
+        $child->parents->add($parent);
+
+        $parent->name = 'abc';
+        $child->name  = 'abc';
+
+        $this->_em->persist($parent);
+        $this->_em->persist($child);
+        $this->_em->flush();
+
+        $parent->name = 'abcd';
+        $child->name  = 'abcd';
+
+        $this->_em->flush();
+
+        self::assertArrayHasKey('parents', $this->_em->getUnitOfWork()->getOriginalEntityData($child));
+    }
+
+    /**
+     * @group #9300
+     */
+    public function testPersistingCollectionAfterFlushWorksAsExpected(): void
+    {
+        $parentOne = new Issue9300Parent();
+        $parentTwo = new Issue9300Parent();
+        $childOne  = new Issue9300Child();
+
+        $parentOne->name   = 'abc';
+        $parentTwo->name   = 'abc';
+        $childOne->name    = 'abc';
+        $childOne->parents = new ArrayCollection([$parentOne]);
+
+        $this->_em->persist($parentOne);
+        $this->_em->persist($parentTwo);
+        $this->_em->persist($childOne);
+        $this->_em->flush();
+
+        // Recalculate change-set -> new original data
+        $childOne->name = 'abcd';
+        $this->_em->flush();
+
+        $childOne->parents = new ArrayCollection([$parentTwo]);
+
+        $this->_em->flush();
+        $this->_em->clear();
+
+        $childOneFresh = $this->_em->find(Issue9300Child::class, $childOne->id);
+        self::assertCount(1, $childOneFresh->parents);
+        self::assertEquals($parentTwo->id, $childOneFresh->parents[0]->id);
+    }
+}
diff --git a/tests/Doctrine/Tests/ORM/UnitOfWorkTest.php b/tests/Doctrine/Tests/ORM/UnitOfWorkTest.php
index df61cd27b59..f04068d3a35 100644
--- a/tests/Doctrine/Tests/ORM/UnitOfWorkTest.php
+++ b/tests/Doctrine/Tests/ORM/UnitOfWorkTest.php
@@ -828,75 +828,6 @@ public function testItThrowsWhenLookingUpIdentifierForUnknownEntity(): void
         $this->expectException(EntityNotFoundException::class);
         $this->_unitOfWork->getEntityIdentifier(new stdClass());
     }
-
-    /**
-     * @group #9300
-     */
-    public function testPersistedCollectionIsPresentInOriginalDataAfterComputeChangeset(): void
-    {
-        $entity = new EntityWithCollection();
-        $entity->children->add(new ChildEntity());
-        $entity->name = 'abc';
-
-        $this->_unitOfWork->persist($entity);
-        $this->_unitOfWork->commit();
-
-        $entity->name = 'abcd';
-        $this->_unitOfWork->computeChangeSets();
-
-        self::assertArrayHasKey('children', $this->_unitOfWork->getOriginalEntityData($entity));
-    }
-}
-
-/**
- * @Entity
- */
-class EntityWithCollection
-{
-    /**
-     * @var Collection|ChildEntity[]
-     * @OneToMany(targetEntity="ChildEntity", mappedBy="parent", cascade={"persist"})
-     */
-    public $children;
-
-    /**
-     * @var int
-     * @Id
-     * @Column(type="integer")
-     * @GeneratedValue
-     */
-    public $id;
-
-    /**
-     * @var string
-     * @Column(type="string")
-     */
-    public $name;
-
-    public function __construct()
-    {
-        $this->children = new ArrayCollection();
-    }
-}
-
-/**
- * @Entity
- */
-class ChildEntity
-{
-    /**
-     * @var int
-     * @Id
-     * @Column(type="integer")
-     * @GeneratedValue
-     */
-    public $id;
-
-    /**
-     * @var int
-     * @ManyToOne(targetEntity="EntityWithCollection", inversedBy="children")
-     */
-    public $parent;
 }
 
 /**
diff --git a/tests/Doctrine/Tests/OrmFunctionalTestCase.php b/tests/Doctrine/Tests/OrmFunctionalTestCase.php
index d15dd58cc92..c907008cba3 100644
--- a/tests/Doctrine/Tests/OrmFunctionalTestCase.php
+++ b/tests/Doctrine/Tests/OrmFunctionalTestCase.php
@@ -335,6 +335,10 @@ abstract class OrmFunctionalTestCase extends OrmTestCase
             Models\Issue5989\Issue5989Employee::class,
             Models\Issue5989\Issue5989Manager::class,
         ],
+        'issue9300' => [
+            Models\Issue9300\Issue9300Child::class,
+            Models\Issue9300\Issue9300Parent::class,
+        ],
     ];
 
     protected function useModelSet(string $setName): void