diff --git a/core/lib/Drupal/Core/Form/FormBuilder.php b/core/lib/Drupal/Core/Form/FormBuilder.php
index d966801..5aaae76 100644
--- a/core/lib/Drupal/Core/Form/FormBuilder.php
+++ b/core/lib/Drupal/Core/Form/FormBuilder.php
@@ -313,8 +313,12 @@ public function buildForm($form_id, FormStateInterface &$form_state) {
    */
   public function rebuildForm($form_id, FormStateInterface &$form_state, $old_form = NULL) {
     $form = $this->retrieveForm($form_id, $form_state);
-    // All rebuilt forms will be cached.
-    $form_state->setCached();
+
+    // We don't allow to set state on GET requests.
+    if ($form_state->isMethodType('POST')) {
+      // All POST rebuilt forms will be cached.
+      $form_state->setCached();
+    }
 
     // If only parts of the form will be returned to the browser (e.g., Ajax or
     // RIA clients), or if the form already had a new build ID regenerated when
diff --git a/core/lib/Drupal/Core/Form/FormState.php b/core/lib/Drupal/Core/Form/FormState.php
index 294846a..92e2eb3 100644
--- a/core/lib/Drupal/Core/Form/FormState.php
+++ b/core/lib/Drupal/Core/Form/FormState.php
@@ -476,7 +476,7 @@ public function getButtons() {
    */
   public function setCached($cache = TRUE) {
     // We determine whether this is the initial rendering of the form.
-    if ($this->isMethodType('GET') && !$this->isSubmitted()) {
+    if ($this->isMethodType('GET')) {
       throw new \LogicException('Initial form rendering is not allowed to cache the form.');
     }
     $this->cache = (bool) $cache;
@@ -487,7 +487,7 @@ public function setCached($cache = TRUE) {
    * {@inheritdoc}
    */
   public function isCached() {
-    return empty($this->no_cache) && $this->cache && $this->isMethodType('POST');
+    return empty($this->no_cache) && $this->cache;
   }
 
   /**
diff --git a/core/tests/Drupal/Tests/Core/Form/FormBuilderTest.php b/core/tests/Drupal/Tests/Core/Form/FormBuilderTest.php
index 9e53645..c02555b 100644
--- a/core/tests/Drupal/Tests/Core/Form/FormBuilderTest.php
+++ b/core/tests/Drupal/Tests/Core/Form/FormBuilderTest.php
@@ -310,11 +310,51 @@ public function testRebuildForm() {
     $form_state->addRebuildInfo('copy', ['#build_id' => TRUE]);
     $this->formBuilder->processForm($form_id, $form, $form_state);
     $this->assertSame($original_build_id, $form['#build_id']);
+    $this->assertTrue($form_state->isCached());
 
     // Rebuild the form again, and assert that there is a new build ID.
     $form_state->setRebuildInfo([]);
     $form = $this->formBuilder->buildForm($form_arg, $form_state);
     $this->assertNotSame($original_build_id, $form['#build_id']);
+    $this->assertTrue($form_state->isCached());
+  }
+
+  /**
+   * Tests the rebuildForm() method for a GET submission.
+   */
+  public function testRebuildFormOnGetRequest() {
+    $form_id = 'test_form_id';
+    $expected_form = $form_id();
+
+    // The form will be built four times.
+    $form_arg = $this->getMock('Drupal\Core\Form\FormInterface');
+    $form_arg->expects($this->exactly(2))
+      ->method('getFormId')
+      ->will($this->returnValue($form_id));
+    $form_arg->expects($this->exactly(4))
+      ->method('buildForm')
+      ->will($this->returnValue($expected_form));
+
+    // Do an initial build of the form and track the build ID.
+    $form_state = new FormState();
+    $form_state->setMethod('GET');
+    $form = $this->formBuilder->buildForm($form_arg, $form_state);
+    $original_build_id = $form['#build_id'];
+
+    // Rebuild the form, and assert that the build ID has not changed.
+    $form_state->setRebuild();
+    $input['form_id'] = $form_id;
+    $form_state->setUserInput($input);
+    $form_state->addRebuildInfo('copy', ['#build_id' => TRUE]);
+    $this->formBuilder->processForm($form_id, $form, $form_state);
+    $this->assertSame($original_build_id, $form['#build_id']);
+    $this->assertFalse($form_state->isCached());
+
+    // Rebuild the form again, and assert that there is a new build ID.
+    $form_state->setRebuildInfo([]);
+    $form = $this->formBuilder->buildForm($form_arg, $form_state);
+    $this->assertNotSame($original_build_id, $form['#build_id']);
+    $this->assertFalse($form_state->isCached());
   }
 
   /**
diff --git a/core/tests/Drupal/Tests/Core/Form/FormStateTest.php b/core/tests/Drupal/Tests/Core/Form/FormStateTest.php
index fe73b5f..aac4094 100644
--- a/core/tests/Drupal/Tests/Core/Form/FormStateTest.php
+++ b/core/tests/Drupal/Tests/Core/Form/FormStateTest.php
@@ -427,7 +427,7 @@ public function testIsCached($cache_key, $no_cache_key, $expected) {
     $this->assertSame($expected, $form_state->isCached());
 
     $form_state->setMethod('GET');
-    $this->assertSame(FALSE, $form_state->isCached());
+    $this->assertSame($expected, $form_state->isCached());
   }
 
   /**
@@ -491,19 +491,6 @@ public function testSetCachedGet() {
   }
 
   /**
-   * @covers ::setCached
-   */
-  public function testSetCachedGetWithSubmission() {
-    $form_state = new FormState();
-    $form_state->setMethod('GET');
-    $form_state->setSubmitted();
-    $form_state->setCached();
-
-    // GET form submissions should not be cached.
-    $this->assertFalse($form_state->isCached());
-  }
-
-  /**
    * @covers ::isMethodType
    * @covers ::setMethod
    *