Does water entering the throat during sniffing in wudu – despite not exaggerating and trying to avoid it – break the fast of a fasting person in Ramadan, and what are the implications for the days in which this occurred with doubt?

The fasting person is commanded not to exaggerate in sniffing water (istīnshāq) for fear of water entering his throat, due to the saying of the Messenger of Allah, peace and blessings be upon him: "And exaggerate in sniffing water unless you are fasting." If the fasting person doubts that something has entered his throat, his fast is valid, and he is not required to make up for it. And if something enters unintentionally and without excessiveness, it does not harm the fast.