She used to recognize the Prophet's ﷺ recitation during the noon prayer by the movement of his beard.
حدثنا عبد الرحمن بن مهدي عن سفيان عن أبي الزعراء
كانت تعرف قراءة النبي ﷺ في الظهر بتحريك لحيته
Its isnad is sahih. Abu Zaraa is Abdullah bin Hani, and he is among the trustworthy Successors. The hadith has already appeared at 20958.