Did the United States Court of Appeals for the Second Circuit err in deciding that a proponent of testimony pursuant to a proffer agreement, entered into with a federal governmental agency after their issuance of a subpoena, is not later protected under that proffer agreement from providing testimony pursuant to a subsequently issued identical subpoena from the same federal agency, in the same proceeding, and seeking the same testimony as that offered pursuant to the proffer agreement?

Did the United States Court of Appeals for the Second Circuit err in deciding that a proponent of testimony pursuant to a proffer agreement is not later protected under that proffer agreement from providing testimony pursuant to a subsequently issued identical subpoena?