Is the supplication of "completing the Qur'an" after reciting it in Ramadan—which is recited over food and then distributed—a Sunnah or an innovation?

A specific supplication for the completion of the Quran is a reprehensible innovation that was not practiced by the Prophet, peace be upon him, nor by the righteous predecessors. Rather, what is reported from the predecessors is supplication after completing the Quran without adhering to a specific supplication or formula. It is permissible for a Muslim to raise his hands and supplicate for whatever good he desires in this world and the hereafter, and there is no specific supplication for completing the Quran to our knowledge. As for reading the supplication for the completion of the Quran over food and distributing it at mourning gatherings or on Thursday evenings, all of that is from innovations, and the Prophet, peace be upon him, forbade innovation in religion.