diff --git a/core/lib/Drupal/Core/Form/FormState.php b/core/lib/Drupal/Core/Form/FormState.php
index 3524ed8..8e6f13a 100644
--- a/core/lib/Drupal/Core/Form/FormState.php
+++ b/core/lib/Drupal/Core/Form/FormState.php
@@ -475,8 +475,10 @@ public function getButtons() {
    * {@inheritdoc}
    */
   public function setCached($cache = TRUE) {
-    if ($this->isMethodType('GET')) {
-      throw new \LogicException('NOPE');
+    // We try to determine whether this is the initial load of the form.
+    // For normal forms it is enough
+    if ($this->isMethodType('GET') && !$this->isSubmitted()) {
+      throw new \LogicException('Initial form rendering is not allowed to cache the form.');
     }
     $this->cache = (bool) $cache;
     return $this;
diff --git a/core/tests/Drupal/Tests/Core/Form/FormStateTest.php b/core/tests/Drupal/Tests/Core/Form/FormStateTest.php
index 985d355..3eca4cc 100644
--- a/core/tests/Drupal/Tests/Core/Form/FormStateTest.php
+++ b/core/tests/Drupal/Tests/Core/Form/FormStateTest.php
@@ -475,7 +475,7 @@ public function testSetCachedPost() {
     $form_state = new FormState();
     $form_state->setMethod('POST');
     $form_state->setCached();
-    $this->assertSame(TRUE, $form_state->isCached());
+    $this->assertTrue($form_state->isCached());
   }
 
   /**
@@ -487,7 +487,19 @@ public function testSetCachedGet() {
     $form_state = new FormState();
     $form_state->setMethod('GET');
     $form_state->setCached();
-    $this->assertSame(TRUE, $form_state->isCached());
+  }
+
+  /**
+   * @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());
   }
 
   /**