Answered by Shaykh Faraz Rabbani
My friend is a very good muslim, he prays 5 times in the mosque but b4 the 2nd and fourth rakahs, he briefly sits and then stands for the next rakah. I understand in the Hanafi madhhab, to do this necessitates sajda sahw. Is this correct?
No, it does not necessitate forgetfulness prostrations, unless he sits still for a lengthy period (over 3 tasbihs) idly not doing anything. This sitting before standing is not disliked if done out of physical need. Otherwise, it is improper.
And Allah knows best.
Wassalam.