Should the worshipper follow the Imam in the Witr prayer if the Imam prays it exactly like the Maghrib prayer?

The follower must follow the imam in matters open to ijtihad, even if he believes that the imam's action is impermissible or that he omitted an obligation. The Sunnah of the Prophet indicates that the imam's error falls upon him, not upon the follower, and that the follower's prayer is valid. If it is possible to advise the imam and explain the Sunnah to him with its proofs, that is better.