Assalamu alaikum,
Respected Mufti Sahab, suppose in fardh namaz of Zuhar while reading alone one reads Attahiyato………… not full but half instead of surah Fathiyah so then he remembers that this is not correct and stops and then reads surah fatiha and completes the full namaz as usual but does not do sajdah sahu. So will the namaz be valid or it got nullified as attahiyato was read instead of Alhumdu Sharif and also no sajdah sahu was made.
Second scenario if after the blunder and rectification sajdah sahu would have been made, then would the namaz become valid or still the namaz would have been void.
Jazzak Allah