Is it obligatory to repeat ablution and prayer after feeling one's ablution nullify during bowing, and then completing the prayer in that state?

A person merely passing by the worshipper and brushing against them does not affect the validity of their ablution or prayer, unless the worshipper becomes certain that their ablution has been nullified by something exiting them. The original state is the continuation of purity, and certainty is not removed by doubt. In the Hadith: "He should not leave until he hears a sound or finds a smell." If he becomes certain that his ablution has been nullified, his prayer becomes invalid, and he must repeat his ablution and prayer.