Is the prayer of one who did not recite the supplication between the two prostrations, thinking it was not obligatory, doubtful in its validity based on the opinion of some scholars that the prayer of one who omits this supplication is invalid?

Reciting remembrances (dhikr) between the two prostrations and uttering glorifications (tasbih) in bowing (rukuʿ) and prostration (sujud) are considered Sunnah according to the majority of scholars, and obligatory according to the Hanbalis. However, the prayer is not invalidated by omitting them due to forgetfulness or ignorance.