Issue #3400311 by kim.pepper: Skip AjaxTest::testAjaxFocus() due to random test failures

core/tests/Drupal/FunctionalJavascriptTests/Ajax/AjaxTest.php

@@ -295,6 +295,7 @@ public function testUiAjaxException() {
    * Tests ajax focus handling.
    */
   public function testAjaxFocus() {
+    $this->markTestSkipped("Skipped due to frequent random test failures. See https://www.drupal.org/project/drupal/issues/3396536");
     $this->drupalGet('/ajax_forms_test_get_form');
 
     $this->assertNotNull($select = $this->assertSession()->elementExists('css', '#edit-select'));