diff --git a/core/tests/Drupal/Tests/HttpKernelUiHelperTrait.php b/core/tests/Drupal/Tests/HttpKernelUiHelperTrait.php
index fc690e828fe8e40b02006fd6f422d9ab55b90ebc..c9fe1ac8e4c17890d4cea71740312e42f67c3ed3 100644
--- a/core/tests/Drupal/Tests/HttpKernelUiHelperTrait.php
+++ b/core/tests/Drupal/Tests/HttpKernelUiHelperTrait.php
@@ -45,6 +45,10 @@ trait HttpKernelUiHelperTrait {
    * Page caching modules will not function, because the
    * CommandLineOrUnsafeMethod caching policy will deny caching.
    *
+   * Some requests may not function correctly because DrupalKernel is not
+   * explicitly designed to handle multiple requests: see
+   * https://www.drupal.org/project/drupal/issues/2708827.
+   *
    * @param string|\Drupal\Core\Url $path
    *   Drupal path or URL to load into Mink controlled browser.
    * @param array $options