Does the Imam bear responsibility on behalf of the worshipper for the prostration of forgetfulness regarding the rakʿahs caught up in a prayer whose beginning was missed, and is the beginning of the prayer meant to be the bowing (rukūʿ) or the opening takbīr (takbīrat al-ihrām)?

The Imam bears the forgetfulness (sahw) of the follower behind him, without any disagreement, and neither of them prostrates for it. However, if the Imam says the salām and the latecomer (masbūq) stands to complete what he missed and makes a mistake in it, he bears his own forgetfulness because the following (qudwah) has ceased. And he must say the takbīrat al-ihrām while standing.

A rak'ah is attained by bowing (rukū'). So, whoever catches the Imam bowing should say the takbīrat al-ihrām while standing and then bow with him, and that rak'ah will be counted for him.