[Name] from Current User system values is NULL

In SmartForms as we are using the [Name] from Current User system values to fetch the user id and pass it to profile in application. But the [Name] value is coming as NULL in the SmartForms and error is thrown from SmartObject as the Userid is required property. For some users the details in the Identity table is present and for few it is not present. Can any one faced in SmartForms earlier and any solution to check the issue.