fix

app/controllers/employee.controller.js

@@ -454,16 +454,22 @@ exports.saveExternalUserPermission = async (req, res) => {
       external_user_id: externalUserId,
       allow_site: allowSite
     });
+    const normalizedTitle = `${title || ""}`.trim();
     const payload = {
       external_user_id: externalUserId,
       allow_site: allowSite,
       username,
       name,
-      title,
       email,
       permissions,
       edit_by: editorId
     };
+    if (normalizedTitle) {
+      payload.title = normalizedTitle;
+    } else if (existing?.title) {
+      // Keep existing title when client does not provide one.
+      payload.title = existing.title;
+    }
     if (!existing) {
       payload.create_by = editorId;
     }