What is the ruling on one who slightly rose during prostration for the first sitting, then returned and completed the same prostration?

If a worshipper intentionally lifts their head from prostration before performing the sufficient prostration, then returns to prostrate, their prayer is invalid. However, if this was due to forgetfulness or ignorance, their prayer is valid. If they lift their head before performing the sufficient prostration, then return to prostrate again, their prayer is valid, and they are not required to perform the prostration of forgetfulness (sujud al-sahw). The sufficient prostration is the stillness of the limbs for a certain period, which some scholars define as the duration of saying "Subhan Allah" once.