What is the ruling for one who prostrated but did not bow behind the imam?
Machine translationRead the Arabic original
The questioner : The questioner says: When the imam finished his supplication, I prostrated but did not bow. I raised my head from prostration when he said, "Allah hears the one who praises Him," and then I completed the prayer with him. What should I do?
The Shaykh : Did he mean to conclude the recitation of the Qur'an? It seems he forgot. This happens often, because it is customary for the imam to make supplication in the qunut of the witr prayer and then prostrate. So it appears he forgot and prostrated. His prayer is valid, if Allah wills, because he added a prostration unintentionally. But when the imam said, "Allah hears the one who praises Him," he realized that the imam was in bowing. We say: stand up, bow, raise your head from bowing, and follow the imam.
The presenter : May Allah reward you.
The Shaykh : Yes.
The Shaykh : Did he mean to conclude the recitation of the Qur'an? It seems he forgot. This happens often, because it is customary for the imam to make supplication in the qunut of the witr prayer and then prostrate. So it appears he forgot and prostrated. His prayer is valid, if Allah wills, because he added a prostration unintentionally. But when the imam said, "Allah hears the one who praises Him," he realized that the imam was in bowing. We say: stand up, bow, raise your head from bowing, and follow the imam.
The presenter : May Allah reward you.
The Shaykh : Yes.
Source
دروس وفتاوى المسجد الحرام لعام 1419هـ - 39 — binothaimeen.net (50:33)
The Arabic text is a machine transcription of the audio recording.