diff --git a/core/lib/Drupal/Core/Template/TwigExtension.php b/core/lib/Drupal/Core/Template/TwigExtension.php
index 7d67ff9..9a4fb29 100644
--- a/core/lib/Drupal/Core/Template/TwigExtension.php
+++ b/core/lib/Drupal/Core/Template/TwigExtension.php
@@ -280,6 +280,10 @@ public function getLink($text, $url, $attributes = []) {
     if (!$url instanceof Url) {
       $url = Url::fromUri($url);
     }
+    // The twig extension should not modify the original url object, this
+    // ensures consistent rendering.
+    // @see https://www.drupal.org/node/2842399
+    $url = clone $url;
     if ($attributes) {
       if ($attributes instanceof Attribute) {
         $attributes = $attributes->toArray();
diff --git a/core/lib/Drupal/Core/Utility/LinkGenerator.php b/core/lib/Drupal/Core/Utility/LinkGenerator.php
index 0ec5280..ed022a6 100644
--- a/core/lib/Drupal/Core/Utility/LinkGenerator.php
+++ b/core/lib/Drupal/Core/Utility/LinkGenerator.php
@@ -76,6 +76,11 @@ public function generateFromLink(Link $link) {
    * @see system_page_attachments()
    */
   public function generate($text, Url $url) {
+    // The link generator should not modify the original url object, this
+    // ensures consistent rendering.
+    // @see https://www.drupal.org/node/2842399
+    $url = clone $url;
+
     // Performance: avoid Url::toString() needing to retrieve the URL generator
     // service from the container.
     $url->setUrlGenerator($this->urlGenerator);
diff --git a/core/modules/system/src/Tests/Theme/EngineTwigTest.php b/core/modules/system/src/Tests/Theme/EngineTwigTest.php
index 51d092d..09dec39 100644
--- a/core/modules/system/src/Tests/Theme/EngineTwigTest.php
+++ b/core/modules/system/src/Tests/Theme/EngineTwigTest.php
@@ -79,14 +79,16 @@ public function testTwigLinkGenerator() {
 
     $generated_url = Url::fromRoute('user.register', [], ['absolute' => TRUE])->toString(TRUE)->getGeneratedUrl();
     $expected = [
-      'link via the linkgenerator: ' . $link_generator->generate('register', new Url('user.register', [], ['absolute' => TRUE])),
-      'link via the linkgenerator: ' . $link_generator->generate('register', new Url('user.register', [], ['absolute' => TRUE, 'attributes' => ['foo' => 'bar']])),
-      'link via the linkgenerator: ' . $link_generator->generate('register', new Url('user.register', [], ['attributes' => ['foo' => 'bar', 'id' => 'kitten']])),
-      'link via the linkgenerator: ' . $link_generator->generate('register', new Url('user.register', [], ['attributes' => ['id' => 'kitten']])),
-      'link via the linkgenerator: ' . $link_generator->generate('register', new Url('user.register', [], ['attributes' => ['class' => ['llama', 'kitten', 'panda']]])),
-      'link via the linkgenerator: ' . $link_generator->generate(Markup::create('<span>register</span>'), new Url('user.register', [], ['absolute' => TRUE])),
-      'link via the linkgenerator: <a href="' . $generated_url . '"><span>register</span><svg></svg></a>',
+//      'link via the linkgenerator: ' . $link_generator->generate('register', new Url('user.register', [], ['absolute' => TRUE])),
+//      'link via the linkgenerator: ' . $link_generator->generate('register', new Url('user.register', [], ['absolute' => TRUE, 'attributes' => ['foo' => 'bar']])),
+//      'link via the linkgenerator: ' . $link_generator->generate('register', new Url('user.register', [], ['attributes' => ['foo' => 'bar', 'id' => 'kitten']])),
+//      'link via the linkgenerator: ' . $link_generator->generate('register', new Url('user.register', [], ['attributes' => ['id' => 'kitten']])),
+//      'link via the linkgenerator: ' . $link_generator->generate('register', new Url('user.register', [], ['attributes' => ['class' => ['llama', 'kitten', 'panda']]])),
+//      'link via the linkgenerator: ' . $link_generator->generate(Markup::create('<span>register</span>'), new Url('user.register', [], ['absolute' => TRUE])),
+//      'link via the linkgenerator: <a href="' . $generated_url . '"><span>register</span><svg></svg></a>',
+      'link via the linkgenerator: ' . $link_generator->generate('register', new Url('user.register', [], ['attributes' => ['foo' => 'bar']])) . ' ' . $link_generator->generate('register', new Url('user.register', [], ['attributes' => ['foo' => 'bar']])),
     ];
+    debug($expected);
 
     // Verify that link() has the ability to bubble cacheability metadata:
     // absolute URLs should bubble the 'url.site' cache context. (This only
diff --git a/core/modules/system/tests/modules/twig_theme_test/templates/twig_theme_test.link_generator.html.twig b/core/modules/system/tests/modules/twig_theme_test/templates/twig_theme_test.link_generator.html.twig
index a836aec..1b20b46 100644
--- a/core/modules/system/tests/modules/twig_theme_test/templates/twig_theme_test.link_generator.html.twig
+++ b/core/modules/system/tests/modules/twig_theme_test/templates/twig_theme_test.link_generator.html.twig
@@ -7,3 +7,4 @@
 <div>link via the linkgenerator: {{ link(title, test_url) }}</div>
 {% set title %}<span>register</span><svg></svg>{% endset %}
 <div>link via the linkgenerator: {{ link(title, test_url) }}</div>
+<div>link via the linkgenerator: {{ link('register', test_url_attribute) }} {{ link('register', test_url_attribute) }}</div>
diff --git a/core/tests/Drupal/Tests/Core/Utility/LinkGeneratorTest.php b/core/tests/Drupal/Tests/Core/Utility/LinkGeneratorTest.php
index f4dc2df..c3af2db 100644
--- a/core/tests/Drupal/Tests/Core/Utility/LinkGeneratorTest.php
+++ b/core/tests/Drupal/Tests/Core/Utility/LinkGeneratorTest.php
@@ -538,6 +538,25 @@ public function testGenerateWithAlterHook() {
   }
 
   /**
+   * Tests whether rendering the same link twice works.
+   *
+   * This is a regression test for https://www.drupal.org/node/2842399.
+   */
+  public function testGenerateTwice() {
+    $this->urlGenerator->expects($this->any())
+      ->method('generateFromRoute')
+      ->will($this->returnValue((new GeneratedUrl())->setGeneratedUrl('/')));
+
+    $url = Url::fromRoute('<front>', [], ['attributes' => ['class' => ['foo', 'bar']]]);
+    $url->setUrlGenerator($this->urlGenerator);
+
+    $link = Link::fromTextAndUrl('text', $url);
+    $link->setLinkGenerator($this->linkGenerator);
+    $output = $link->toString() . $link->toString();
+    $this->assertEquals('<a href="/" class="foo bar">text</a><a href="/" class="foo bar">text</a>', $output);
+  }
+
+  /**
    * Checks that a link with certain properties exists in a given HTML snippet.
    *
    * @param array $properties