Question: One Imam led same day’s Zuhr Salah in two different places. Is his leading in two different places of Zuhr Salah valid?
Answer: The first jama’ah of Zuhr Salah for every Musallis will be valid and the second Jama’ah will be void (invalid) for the Musallis. As a result, it will be considered for the Imam to be Nafl Salah and Fard for Musallis.
Thus, the Musallis who are performing Fard cannot be following the Imam who is doing Nafl. Therefore, those Musallis of scond place need to perform the Zuhr Salah again.
Reference: [1]Radd al Muhtar vol-2:324