The Imaam did not Sit after two Rakaahs

Q: Salaah-307: The Imaam leading the Taraaweeh salaah did not sit after two Rakaahs and went on to complete four Rakaahs. He also performed Sajdah Sahw before the Salaam. Need the salaah be repeated?

Answer: Two Rakaahs of the four will be regarded as Taraaweeh and two Will be Nafl. And Allaah knows best what is most correct.

Fatawa Rahimiyyah vol.2