Text Tag not rendering properly

Hello - I have a couple of text tags that are not displaying properly. I have a required signature for the signer, then a required field for their full name, then an optional field for their title. I've added these fields to the uploaded document as follows:

{{Sig_es_:signer:signature}}

  {{N_es_:signer:fullname}}

  {{Ttl_es_:signer:title}}


When I preview the document, the fields are rendered with a red border (which I thought would indicate 'required'...). When I send a test document, I see the signature field properly, but there is no field for the full name, and the title field is marked as required.

Any help appreciated - thanks