ticket workflow: owner email macro is not expanded into email To: template

In a workflow Email action, if the 'to:' field contains $(assigned_user_id : (Users) email1) then it is expanded to '' (empty string). So for example [email protected],$(assigned_user_id : (Users) email1),[email protected] is expanded to [email protected],,[email protected].

The same macro $(assigned_user_id : (Users) email1) in the email template body is correctly expanded to the email of the owner of the ticket.

vTiger 8.3