A Signature message will only resend messages if an error is encountered
On line 1255 of src/message.c the handling of OTRL_MSGTYPE_SIGNATURE starts. It calls otrl_auth_handle_signature, and after that call checks if err is true or if haveauthmsg is true. If either are true send_or_error_auth will be called, and then maybe_resend.
However, the problem is that otrl_auth_handle_signature will never set haveauthmsg to true. In fact, otrl_auth_handle_signature assigns haveauthmsg three times, but every time it assigns 0. Thus, resending of stored messages will only happen if an error is encountered during handling of signature messages, thus contradicting the specification.
(from redmine: created on 2015-08-07)