Performing the Taraaweeh salaah Behind an Imaam who is Performing the Witr salaah

Q: Salaah-189: The Imaam mistakenly started the Witr salaah after performing only sixteen Rakaahs of the Taraaweeh salaah. The followers followed him thinking that he was performing the Taraaweeh salaah and it was only after the Salaam that they informed him that four Rakaahs of the Taraaweeh salaah was still outstanding. Was the Witr salaah valid? The Imaam did however repeat the Witr salaah.

Answer: Although the first Witr salaah of the Imaam's was valid, neither of the two salaah was valid for the followers because they had no intention of performing Witr the first time and although they had the intention the second time they were following someone who had already performed his Witr salaah.

Fatawa Rahimiyyah vol.2