The Messenger of Allah ﷺ became forgetful during the prayer, so he performed the two prostrations of forgetfulness after speaking.
حدثنا أبو معاوية حدثنا الأعمش عن إبراهيم عن علقمة
أن رسول الله ﷺ سها في الصلاة فسجد سجدتي السهو بعد الكلام
Its chain of transmission is sahih, and it is an abridgment of 4282. See also 4348.