´It was narrated that Ibn Sirin said:` "Some of those who prayed the Subh prayer with the Messenger of Allah (ﷺ) narrated to me that when he said: Sami'Allahu liman hamidah (Allah hears those who praise Him)' in the second rak'ah, he stood for a while."
Hadith Referenceسنن نسائي / كتاب التطبيق / 1073
Hadith Gradingالألبانی:صحيح | زبیر علی زئی:ضعيف، إسناده ضعيف، ابو داود (1446) انوار الصحيفه، صفحه نمبر 329
1073. Commentary: The Imam, rahimahullah, has perhaps interpreted standing for a short while as referring to the qunoot, although the Prophet, sallallahu alayhi wa sallam, used to recite certain supplications and remembrances even after rising from bowing (ruku‘). As for qunoot, it is recited aloud and with raised hands, as has been explicitly mentioned in the narrations. [مسند أحمد : 3/3]
Source: Sunan Nasa'i: Translation and Benefits by Shaykh Hafiz Muhammad Amin Hafizullah, Page: 1073