Ibn Sirin narrates: Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) and Sayyiduna Hudhayfah (may Allah be pleased with him) used to forbid people (the narrator is unsure; perhaps the words are:) they would make those whom they saw offering voluntary prayers before the imam came out sit down; this was on the day of Eid.
Al-Tabarani recorded it in al-Mu'jam al-Kabir through various chains, in some of which it says: I was informed that Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) and Sayyiduna Hudhayfah (may Allah be pleased with him) (used to do so).
Thus this narration is mursal (with a missing link), and its chain is sahih (authentic).