diff --git a/core/modules/path/src/Plugin/Field/FieldType/PathItem.php b/core/modules/path/src/Plugin/Field/FieldType/PathItem.php
index 32e88224cc..76dddc20e8 100644
--- a/core/modules/path/src/Plugin/Field/FieldType/PathItem.php
+++ b/core/modules/path/src/Plugin/Field/FieldType/PathItem.php
@@ -51,28 +51,33 @@ public function preSave() {
    * {@inheritdoc}
    */
   public function postSave($update) {
+    /** @var \Drupal\Core\Path\AliasStorageInterface $alias_storage */
+    $alias_storage = \Drupal::service('path.alias_storage');
+
     // Only process a non-empty alias.
     $entity = $this->getEntity();
+    $canonical = '/' . $entity->toUrl()->getInternalPath();
     if ($entity->getEntityType()->isRevisionable() && !$entity->isDefaultRevision()) {
       $source = '/' . $entity->toUrl('revision')->getInternalPath();
     }
     else {
-      $source = '/' . $entity->toUrl()->getInternalPath();
+      $source = $canonical;
     }
 
     if ($this->alias && (!$update || $source != $this->source)) {
-      if ($path = \Drupal::service('path.alias_storage')->save($source, $this->alias, $this->getLangcode())) {
-          $this->pid = $path['pid'];
+      $default_alias = $alias_storage->load(['source' => $canonical]);
+      if ($default_alias['alias'] != $this->alias && $path = $alias_storage->save($source, $this->alias, $this->getLangcode())) {
+        $this->pid = $path['pid'];
       }
     }
     else {
       // Delete old alias if user erased it.
       if (!$this->alias) {
-        \Drupal::service('path.alias_storage')->delete(['source' => $source]);
+        $alias_storage->delete(['source' => $source]);
       }
       // Only save a non-empty alias.
       elseif ($source) {
-        \Drupal::service('path.alias_storage')->save($source, $this->alias, $this->getLangcode(), $this->pid);
+        $alias_storage->save($source, $this->alias, $this->getLangcode(), $this->pid);
       }
     }
   }
diff --git a/core/modules/path/src/Plugin/Field/FieldWidget/PathWidget.php b/core/modules/path/src/Plugin/Field/FieldWidget/PathWidget.php
index a6805c5b91..8f5bcb79d7 100644
--- a/core/modules/path/src/Plugin/Field/FieldWidget/PathWidget.php
+++ b/core/modules/path/src/Plugin/Field/FieldWidget/PathWidget.php
@@ -28,16 +28,17 @@ public function formElement(FieldItemListInterface $items, $delta, array $elemen
     $entity = $items->getEntity();
     $path = [];
     if (!$entity->isNew()) {
-      if ($entity->getEntityType()->isRevisionable() && !$entity->isDefaultRevision()) {
-        $conditions = ['source' => '/' . $entity->toUrl('revision')->getInternalPath()];
+      if ($items->getLangcode() != LanguageInterface::LANGCODE_NOT_SPECIFIED) {
+        $conditions = ['langcode' => $items->getLangcode()];
       }
-      else {
-        $conditions = ['source' => '/' . $entity->toUrl()->getInternalPath()];
+      if ($entity->getEntityType()->isRevisionable() && !$entity->isDefaultRevision()) {
+        $conditions['source'] = '/' . $entity->toUrl('revision')->getInternalPath();
+        $path = \Drupal::service('path.alias_storage')->load($conditions);
       }
-      if ($items->getLangcode() != LanguageInterface::LANGCODE_NOT_SPECIFIED) {
-        $conditions['langcode'] = $items->getLangcode();
+      if ($path === FALSE) {
+        $conditions['source'] = '/' . $entity->toUrl()->getInternalPath();
+        $path = \Drupal::service('path.alias_storage')->load($conditions);
       }
-      $path = \Drupal::service('path.alias_storage')->load($conditions);
       if ($path === FALSE) {
         $path = [];
       }
diff --git a/core/modules/path/tests/src/Functional/PathContentModerationTest.php b/core/modules/path/tests/src/Functional/PathContentModerationTest.php
index 7b2c66057c..b9d9f8305e 100644
--- a/core/modules/path/tests/src/Functional/PathContentModerationTest.php
+++ b/core/modules/path/tests/src/Functional/PathContentModerationTest.php
@@ -26,9 +26,11 @@ class PathContentModerationTest extends BrowserTestBase {
   protected function setUp() {
     parent::setUp();
 
+    // Created a content type.
     $node_type = NodeType::create(['name' => 'moderated', 'type' => 'moderated']);
     $node_type->save();
 
+    // Set the content type as moderated.
     $workflow = Workflow::load('editorial');
     $workflow->getTypePlugin()->addEntityTypeAndBundle('node', 'moderated');
     $workflow->save();
@@ -37,6 +39,7 @@ protected function setUp() {
   }
 
   public function testNodePathAlias() {
+    // Create some moderated content with a path alias.
     $this->drupalPostForm('node/add/moderated', [
       'title[0][value]' => 'moderated content',
       'path[0][alias]' => '/moderated-content',
@@ -46,41 +49,41 @@ public function testNodePathAlias() {
     $this->drupalGet('/moderated-content');
     $this->assertSession()->pageTextContains('moderated content');
 
+    // Add a forward revision with the same alias.
     $this->drupalPostForm('node/' . $node->id() . '/edit', [
       'title[0][value]' => 'forward revision',
-      'path[0][alias]' => '/forward-revision',
+      'path[0][alias]' => '/moderated-content',
     ], t('Save and Create New Draft'));
 
-    $this->drupalGet('/forward-revision');
-    $this->assertSession()->pageTextNotContains('moderated content');
-    $this->assertSession()->pageTextContains('forward revision');
+    // Check the alias still shows the default content.
     $this->drupalGet('/moderated-content');
     $this->assertSession()->pageTextNotContains('forward revision');
     $this->assertSession()->pageTextContains('moderated content');
 
+    // Add a third revision, updating alias.
     $this->drupalPostForm('node/' . $node->id() . '/edit', [
       'title[0][value]' => 'revision three',
       'path[0][alias]' => '/revision-three',
     ], t('Save and Create New Draft'));
 
+    // Check both aliases return what we'd expect.
     $this->drupalGet('/revision-three');
     $this->assertSession()->pageTextNotContains('moderated content');
     $this->assertSession()->pageTextNotContains('forward revision');
     $this->assertSession()->pageTextContains('revision three');
-    $this->drupalGet('/forward-revision');
-    $this->assertSession()->pageTextNotContains('moderated content');
-    $this->assertSession()->pageTextContains('forward revision');
-    $this->assertSession()->pageTextNotContains('revision three');
     $this->drupalGet('/moderated-content');
     $this->assertSession()->pageTextNotContains('forward revision');
     $this->assertSession()->pageTextContains('moderated content');
     $this->assertSession()->pageTextNotContains('revision three');
 
+    // Add another forward revision with no alias.
     $this->drupalPostForm('node/' . $node->id() . '/edit', [
       'title[0][value]' => 'revision four',
       'path[0][alias]' => '',
     ], t('Save and Create New Draft'));
 
+    // The first two aliases should still work, and the revision with no alias
+    // should work on the revision path.
     $this->drupalGet('/node/1/revisions/4/view');
     $this->assertSession()->pageTextNotContains('moderated content');
     $this->assertSession()->pageTextNotContains('forward revision');
@@ -91,11 +94,6 @@ public function testNodePathAlias() {
     $this->assertSession()->pageTextNotContains('forward revision');
     $this->assertSession()->pageTextContains('revision three');
     $this->assertSession()->pageTextNotContains('revision four');
-    $this->drupalGet('/forward-revision');
-    $this->assertSession()->pageTextNotContains('moderated content');
-    $this->assertSession()->pageTextContains('forward revision');
-    $this->assertSession()->pageTextNotContains('revision three');
-    $this->assertSession()->pageTextNotContains('revision four');
     $this->drupalGet('/moderated-content');
     $this->assertSession()->pageTextNotContains('forward revision');
     $this->assertSession()->pageTextContains('moderated content');