diff --git a/core/modules/user/tests/src/Functional/UserMailChangeTest.php b/core/modules/user/tests/src/Functional/UserMailChangeTest.php
index b3bb9522a1..8cd7c1dd5a 100644
--- a/core/modules/user/tests/src/Functional/UserMailChangeTest.php
+++ b/core/modules/user/tests/src/Functional/UserMailChangeTest.php
@@ -48,6 +48,16 @@ protected function setUp() {
   public function testMailChange() {
     $this->drupalLogin($this->account);
 
+    // Ensure a time between the user last login and the time the account edit
+    // is posted. A human cannot login, edit the account and post the changes
+    // within the same second. But tests occasionally are running all steps in
+    // the same timestamp, so that the mail change URL timestamp equals the user
+    // last login timestamp. Later, in this test, when we try to reuse the
+    // expired link, we're still within the timestamp when the user last has
+    // logged in and we cannot experience a time difference as the user last
+    // login time has seconds as granularity.
+    sleep(1);
+
     // Change the user email address.
     $new_mail = $this->getRandomEmailAddress();
     $edit = [