Error after wrong e-mail

Dear developer of this great plugin,

I’ve got a question: When the user enters a wrong e-mail on login, the plugins returns the error message but also an PHP error:

NOTICE: Trying to get property of non-object in

It points to line 126 and 127:

$user_login = $user_data->data->user_login;
$user_email = $user_data->data->user_email;

Any idea what can cause this error?

Thanks!