diff --git a/core/modules/book/src/BookManager.php b/core/modules/book/src/BookManager.php
index 402776c..3db359b 100644
--- a/core/modules/book/src/BookManager.php
+++ b/core/modules/book/src/BookManager.php
@@ -278,7 +278,13 @@ public function updateOutline(NodeInterface $node) {
 
     // Prevent changes to the book outline if the node being saved is not the
     // default revision.
-    $updated = !$new && (($original = $this->loadBookLink($node->id(), FALSE)) && ($node->book['bid'] != $original['bid'] || $node->book['pid'] != $original['pid']));
+    $updated = FALSE;
+    if (!$new) {
+      $original = $this->loadBookLink($node->id(), FALSE);
+      if ($node->book['bid'] != $original['bid'] || $node->book['pid'] != $original['pid'] || $node->book['weight'] != $original['weight']) {
+        $updated = TRUE;
+      }
+    }
     if (($new || $updated) && !$node->isDefaultRevision()) {
       return FALSE;
     }
diff --git a/core/modules/book/tests/src/Functional/BookContentModerationTest.php b/core/modules/book/tests/src/Functional/BookContentModerationTest.php
index 4411a87..c42feeb 100644
--- a/core/modules/book/tests/src/Functional/BookContentModerationTest.php
+++ b/core/modules/book/tests/src/Functional/BookContentModerationTest.php
@@ -78,6 +78,17 @@ public function testBookWithForwardRevisions() {
     $this->checkBookNode($book_1, [$book_1_nodes[0], $book_1_nodes[3], $book_1_nodes[4]], FALSE, FALSE, $book_1_nodes[0], []);
     $this->checkBookNode($book_1_nodes[0], [$book_1_nodes[1], $book_1_nodes[2]], $book_1, $book_1, $book_1_nodes[1], [$book_1]);
 
+    // Try to change the weight of Node 2.
+    $edit['book[weight]'] = 2;
+    $this->drupalPostForm('node/' . $book_1_nodes[1]->id() . '/edit', $edit, t('Save and Create New Draft'));
+
+    $this->assertSession()->pageTextContains('You can only change the book outline for the published version of this content.');
+
+    // Check that the book outline did not change.
+    $this->book = $book_1;
+    $this->checkBookNode($book_1, [$book_1_nodes[0], $book_1_nodes[3], $book_1_nodes[4]], FALSE, FALSE, $book_1_nodes[0], []);
+    $this->checkBookNode($book_1_nodes[0], [$book_1_nodes[1], $book_1_nodes[2]], $book_1, $book_1, $book_1_nodes[1], [$book_1]);
+
     // Save a new draft revision for the node without any changes and check that
     // the error message is not displayed.
     $this->drupalPostForm('node/' . $book_1_nodes[1]->id() . '/edit', [], t('Save and Create New Draft'));
diff --git a/core/modules/book/tests/src/Kernel/BookForwardRevisionTest.php b/core/modules/book/tests/src/Kernel/BookForwardRevisionTest.php
index 466f96c..df3e5bf 100644
--- a/core/modules/book/tests/src/Kernel/BookForwardRevisionTest.php
+++ b/core/modules/book/tests/src/Kernel/BookForwardRevisionTest.php
@@ -51,6 +51,10 @@ public function testBookWithForwardRevisions() {
     $book_1 = Node::create(['title' => $this->randomString(), 'type' => $content_type->id()]);
     $book_1->book['bid'] = 'new';
     $book_1->save();
+    $book_1_child = Node::create(['title' => $this->randomString(), 'type' => $content_type->id()]);
+    $book_1_child->book['bid'] = $book_1->id();
+    $book_1_child->book['pid'] = $book_1->id();
+    $book_1_child->save();
 
     $book_2 = Node::create(['title' => $this->randomString(), 'type' => $content_type->id()]);
     $book_2->book['bid'] = 'new';
@@ -72,8 +76,25 @@ public function testBookWithForwardRevisions() {
     $child->setNewRevision(TRUE);
     $child->isDefaultRevision(FALSE);
 
-    $return = $book_manager->updateOutline($child);
-    $this->assertFalse($return, 'A forward revision can not change the book outline.');
+    $this->assertFalse($book_manager->updateOutline($child), 'A forward revision can not change the book outline.');
+
+    // Check that the API doesn't allow us to change the book parent for
+    // forward revisions.
+    $child = \Drupal::entityTypeManager()->getStorage('node')->loadUnchanged($child->id());
+    $child->book['pid'] = $book_1_child->id();
+    $child->setNewRevision(TRUE);
+    $child->isDefaultRevision(FALSE);
+
+    $this->assertFalse($book_manager->updateOutline($child), 'A forward revision can not change the book outline.');
+
+    // Check that the API doesn't allow us to change the book weight for
+    // forward revisions.
+    $child = \Drupal::entityTypeManager()->getStorage('node')->loadUnchanged($child->id());
+    $child->book['weight'] = 2;
+    $child->setNewRevision(TRUE);
+    $child->isDefaultRevision(FALSE);
+
+    $this->assertFalse($book_manager->updateOutline($child), 'A forward revision can not change the book outline.');
   }
 
 }