Is it considered a mistake in prayer and an innovation (bid‘ah) for the worshiper to lower his head after the salutation to the right, and then salute to the left?

There is no textual evidence from Islamic law for lowering the head between the two salutations, and none of the scholars have mentioned this characteristic in the salutation. The Prophetic traditions describe the salutation as turning right and left until the whiteness of the cheek is seen, like the hadith (definition) of Ibn Mas'ud and Sa'd. The absence of any mention of lowering the head in these hadiths makes it an innovation, and "every innovation is a heresy, every heresy is misguidance, and every misguidance is in the Fire."