ANSWER:

If the imam sat mistakenly in the 3rd, you should notify him by saying subhana Allah 

If he doesn’t listen and rectify his mistake by standing up to the 4th, you must leave him and stand up to your fourth and finish you prayer alone.

It is not permissible to follow him in that as it is not permissible to follow him if he were to stand up to the 5th rakah for example.

The prayer is invalid for dropping a whole rakah and that can’t be compensated by sujood  assahu.

QUESTION: One day while praying ‘Asr in the mosque, the Imam mistakenly sat in the 3rd rakah and recited Tashahhud. I initially got up and stood but later sat down again when I saw that the Imam did not rise up for the “4th rakah” but I did not recite the tashahhud in the 3rd rakah like the Imam. The Imam along with everyone of us offered sujood-as-sahw before concluding the prayer. Did I do anything wrong?

Prayer |