What is the ruling on forgetting one circuit of Sa'i during Umrah for the Mutamatti' after exiting Ihram, and is the Hajj valid in this case?

If a pilgrim (Mu'tamir) forgets one or more circuits of the Sa'i (ritual circumambulation between Safa and Marwa), then their Sa'i is not complete, and they must return to their state of ihram and complete what they missed, building upon what they had previously performed. The majority of scholars prefer that the pilgrim restart the Sa'i from the beginning, because performing the circuits of Sa'i consecutively (Muwalah) is a Sunnah and not a condition. After completing the Sa'i, they should shave or shorten their hair. Their previous shaving or shortening is not counted because it occurred before the completion of the Sa'i. There is no fidyah (expiatory offering) upon them for doing this forgetfully, and their 'Umrah is valid.