'Umar bin 'Ata reported that Nafi' bin Jubair sent him to Sa'ib bin Ukht Namir to ask him about something that Mu'awiyah had seen him doing in Salat (prayer). He said

"Yes, I performed the Friday prayer along with him in the enclosure (Maqsurah), and when the Imam concluded the Salat with Taslim, I stood up in my place and performed the Sunnah prayer. When Mu'awiyah went home, he sent for me (and when I came) he said: "Never do again what you have done. When you have observed the Friday prayer, you must not start another Sunnah prayer till you have spoken to someone or have shifted your place; because the Messenger of Allah (ﷺ) ordered us not to follow up the congregational Salat with any other Salat until we have talked (to some one) or moved from the place."

[Muslim].