diff --git a/core/modules/breakpoint/lib/Drupal/breakpoint/Entity/Breakpoint.php b/core/modules/breakpoint/lib/Drupal/breakpoint/Entity/Breakpoint.php
index b2e74db..700315c 100644
--- a/core/modules/breakpoint/lib/Drupal/breakpoint/Entity/Breakpoint.php
+++ b/core/modules/breakpoint/lib/Drupal/breakpoint/Entity/Breakpoint.php
@@ -109,7 +109,10 @@ class Breakpoint extends ConfigEntityBase implements BreakpointInterface {
    * {@inheritdoc}
    */
   public function id() {
-    return $this->sourceType . '.' . $this->source . '.' . $this->name;
+    if (!isset($this->id)) {
+      $this->id = $this->sourceType . '.' . $this->source . '.' . $this->name;
+    }
+    return $this->id;
   }
 
   /**
diff --git a/core/modules/breakpoint/lib/Drupal/breakpoint/Entity/BreakpointGroup.php b/core/modules/breakpoint/lib/Drupal/breakpoint/Entity/BreakpointGroup.php
index 1154dd7..1d0833d 100644
--- a/core/modules/breakpoint/lib/Drupal/breakpoint/Entity/BreakpointGroup.php
+++ b/core/modules/breakpoint/lib/Drupal/breakpoint/Entity/BreakpointGroup.php
@@ -111,7 +111,10 @@ public function save() {
    * {@inheritdoc}
    */
   public function id() {
-    return $this->sourceType . '.' . $this->source . '.' . $this->name;
+    if (!isset($this->id)) {
+      $this->id = $this->sourceType . '.' . $this->source . '.' . $this->name;
+    }
+    return $this->id;
   }
 
   /**
diff --git a/core/modules/breakpoint/lib/Drupal/breakpoint/Tests/BreakpointAPITest.php b/core/modules/breakpoint/lib/Drupal/breakpoint/Tests/BreakpointAPITest.php
index 85d0711..e132280 100644
--- a/core/modules/breakpoint/lib/Drupal/breakpoint/Tests/BreakpointAPITest.php
+++ b/core/modules/breakpoint/lib/Drupal/breakpoint/Tests/BreakpointAPITest.php
@@ -46,7 +46,7 @@ public function testConfigName() {
     $this->assertTrue($exception, 'breakpoint_config_name: An exception is thrown when an invalid sourceType is entered.');
 
     // Try an invalid source.
-    $breakpoint->id = '';
+    $breakpoint = $breakpoint->createDuplicate();
     $breakpoint->sourceType = Breakpoint::SOURCE_TYPE_USER_DEFINED;
     $breakpoint->source = 'custom*_module source';
 
@@ -60,7 +60,7 @@ public function testConfigName() {
     $this->assertTrue($exception, 'breakpoint_config_name: An exception is thrown when an invalid source is entered.');
 
     // Try an invalid name (make sure there is at least once capital letter).
-    $breakpoint->id = '';
+    $breakpoint = $breakpoint->createDuplicate();
     $breakpoint->source = 'custom_module';
     $breakpoint->name = drupal_ucfirst($this->randomName());
 
@@ -74,7 +74,7 @@ public function testConfigName() {
     $this->assertTrue($exception, 'breakpoint_config_name: An exception is thrown when an invalid name is entered.');
 
     // Try a valid breakpoint.
-    $breakpoint->id = '';
+    $breakpoint = $breakpoint->createDuplicate();
     $breakpoint->name = drupal_strtolower($this->randomName());
     $breakpoint->mediaQuery = 'all';
 
diff --git a/core/modules/breakpoint/lib/Drupal/breakpoint/Tests/BreakpointGroupAPITest.php b/core/modules/breakpoint/lib/Drupal/breakpoint/Tests/BreakpointGroupAPITest.php
index 3751c81..7a563f6 100644
--- a/core/modules/breakpoint/lib/Drupal/breakpoint/Tests/BreakpointGroupAPITest.php
+++ b/core/modules/breakpoint/lib/Drupal/breakpoint/Tests/BreakpointGroupAPITest.php
@@ -49,6 +49,7 @@ public function testConfigName() {
     $this->assertTrue($exception, 'An exception is thrown when an invalid sourceType is entered.');
 
     // Try an invalid source.
+    $breakpoint_group = $breakpoint_group->createDuplicate();
     $breakpoint_group->name = '';
     $breakpoint_group->sourceType = Breakpoint::SOURCE_TYPE_USER_DEFINED;
     $breakpoint_group->source = 'custom*_module source';
@@ -63,6 +64,7 @@ public function testConfigName() {
     $this->assertTrue($exception, 'An exception is thrown when an invalid source is entered.');
 
     // Try a valid breakpoint_group.
+    $breakpoint_group = $breakpoint_group->createDuplicate();
     $breakpoint_group->name = 'test';
     $breakpoint_group->source = 'custom_module_source';