Does the prayer become invalid if "Subhana Rabbi Al-A'zham" is said during Rukoo' instead of "Subhana Rabbi Al-A'zhim"?

Scholars differed concerning the ruling on reciting tasbeeh (glorification) in rukūʿ (bowing). The majority of scholars consider it a sunnah (recommended act), meaning the prayer is valid even if it is omitted. However, Ahmad (referring to Imam Ahmad ibn Hanbal) views it as obligatory, and the prayer is invalidated if it is deliberately omitted.

Several forms of tasbeeh in rukūʿ have been reported from the Prophet, peace and blessings be upon him, including: "Subḥāna Rabbī al-ʿAẓīm" (Glory be to my Lord, the Most Great), "Subḥāna Rabbī al-ʿAẓīm wa bi ḥamdihi" (Glory be to my Lord, the Most Great, and with His praise), "Subbūḥun Quddūsun Rabbu al-Malāʾikati wa ar-Rūḥ" (All-Glorious, All-Holy, Lord of the angels and the Spirit), "Subḥānaka Allāhumma Rabbanā wa bi ḥamdika, Allāhumma ighfir lī" (Glory be to You, O Allah, our Lord, and with Your praise, O Allah, forgive me), and "Allāhumma laka rakaʿtu wa bika āmant..." (O Allah, to You I have bowed, and in You I have believed...).

The phrase "Subḥāna Rabbī al-Aʿẓam" (Glory be to my Lord, the Most Greatest) has not been reported among the adhkār (remembrances) of rukūʿ. However, whoever recites it has still performed tasbeeh and glorification, because "al-Aʿẓam" (the Most Greatest) is more emphatic than "al-ʿAẓīm" (the Most Great).

Shaykh al-Islam Ibn Taymiyyah holds that the essence of tasbeeh is obligatory in prayer, and a specific wording is not required. However, it is best to adhere to the reported wording, while allowing for variation among the authentically transmitted formulas.