What are the consequences for one who does not perform the prostrations of forgetfulness (sujood al-sahw) in an obligatory prayer, whether praying alone or behind an imam?

If a worshiper intentionally omits the obligatory prostrations of forgetfulness (sujud as-sahw), their prayer becomes invalid. However, if they forget them and remember after the taslim (salutation of peace), they should perform them, provided the interval is not prolonged or they have not exited the mosque. If the Imam forgets the prostrations of forgetfulness, the congregant (ma'mum) should not perform them alone. Rather, they should conclude the prayer with the Imam and then remind him so that the Imam can perform the prostrations, and the congregant will prostrate with him.