The World Federation One Stop Fiqh

Ruling 1206

If after performing ṣalāt al‐iḥtiyāṭ one realises that the deficiency in the number of rakʿahs in his prayer was less than the number of rakʿahs in his ṣalāt al‐iḥtiyāṭ – for example, for the doubt between two and four rakʿahs, he performs two rakʿahs of ṣalāt al‐iḥtiyāṭ and later realises that he had performed three rakʿahs – in such a case, he must perform the [original] prayer again.