diff --git a/src/infrastructure/customfield/field/PhabricatorCustomFieldList.php b/src/infrastructure/customfield/field/PhabricatorCustomFieldList.php
--- a/src/infrastructure/customfield/field/PhabricatorCustomFieldList.php
+++ b/src/infrastructure/customfield/field/PhabricatorCustomFieldList.php
@@ -89,7 +89,7 @@
       $field_handles = array_select_keys($handles, $phids[$field_key]);
 
       $instructions = $field->getInstructionsForEdit();
-      if (strlen($instructions)) {
+      if (phutil_nonempty_string($instructions)) {
         $form->appendRemarkupInstructions($instructions);
       }