What is the ruling on someone who joined congregational prayer after the first bowing (rukūʿ), and the imam made a mistake and prayed an extra bowing (rakʿah); does the follower complete the bowing (rakʿah) they missed after the prostration of forgetfulness (sujūd al-sahw), or is the extra bowing (rakʿah) prayed by the imam sufficient?

Scholars have differed on the issue of whether a latecomer (masbuq) can count an extra prostration; the correct view is that he cannot count it, but rather must make up what he missed after the imam's salām.

As for the prostrations of forgetfulness (sujūd as-sahw), if the latecomer catches one rak'ah with the imam, he prostrates with him for the forgetfulness that occurred before the salām, and he prostrates after his own salām for what occurred after the salām. If he did not catch a rak'ah, then he only prostrates for his own forgetfulness.