During the month of Ramadhan sometimes the Hafiz/Imam forgets to make the Qunoot in the third rakaat of the Salaat before the Ruku. In order to compensate for this, some of them make this Qunoot after coming up from Ruku and then repeat another Ruku (after it) before proceeding to Sajda. Will the repetition of the Ruku render the Salaat invalid?
Repetition of the Ruku will not render the Salaat invalid. However he would have to perform a Sijdah Sahwa to compensate for the mistake.
(Tahtawi – Pg. 250 / Halbi Kabir – Pg. 460-461 / Kifayatul Mufti – Vol. 3 – Pg. 342 / Shaami – Vol. 2 – Pg. 9 / Fatawa Darul Uloom Deoband – Vol. 4 – Pg. 156)
And Allah knows best.
Mufti Waseem Khan
This answer was collected from DarulUloomTT.net, which is operated under the supervision of Mufti Waseem Khan from Darul Uloom Trinidad and Tobago.