diff -u b/core/modules/field/tests/src/FunctionalJavascript/NestedFormTest.php b/core/modules/field/tests/src/FunctionalJavascript/NestedFormTest.php
--- b/core/modules/field/tests/src/FunctionalJavascript/NestedFormTest.php
+++ b/core/modules/field/tests/src/FunctionalJavascript/NestedFormTest.php
@@ -215,13 +215,12 @@
 
     // Trigger add on the base entity.
     $add_more_unlimited->click();
-    $assert_session->assertWaitOnAjaxRequest();
 
     // Validate the fields are added correctly, retaining the original values.
-    $field_unlimited_2 = $page->findField('field_unlimited[2][value]');
-    $field_unlimited_3 = $page->findField('field_unlimited[3][value]');
-    $field_entity_2_unlimited_2 = $page->findField('entity_2[field_unlimited][2][value]');
-    $field_entity_2_unlimited_3 = $page->findField('entity_2[field_unlimited][3][value]');
+    $field_unlimited_2 = $assert_session->waitForField('field_unlimited[2][value]');
+    $field_unlimited_3 = $assert_session->waitForField('field_unlimited[3][value]');
+    $field_entity_2_unlimited_2 = $assert_session->waitForField('entity_2[field_unlimited][2][value]');
+    $field_entity_2_unlimited_3 = $assert_session->waitForField('entity_2[field_unlimited][3][value]');
     $this->assertEquals(3, $field_unlimited_0->getValue());
     $this->assertEquals(2, $field_unlimited_1->getValue());
     $this->assertEmpty($field_unlimited_2->getValue());
@@ -235,10 +234,9 @@
     $field_entity_2_unlimited_1->setValue('14');
     $field_entity_2_unlimited_2->setValue('15');
     $entity_2_add_more_unlimited->click();
-    $assert_session->assertWaitOnAjaxRequest();
 
     // Validate the values are as expected after adding more.
-    $field_entity_2_unlimited_3 = $page->findField('entity_2[field_unlimited][3][value]');
+    $field_entity_2_unlimited_3 = $assert_session->waitForField('entity_2[field_unlimited][3][value]');
     $this->assertEquals(13, $field_entity_2_unlimited_0->getValue());
     $this->assertEquals(14, $field_entity_2_unlimited_1->getValue());
     $this->assertEquals(15, $field_entity_2_unlimited_2->getValue());