Should a latecomer who did not catch a full rak'ah with the Imam wait for the Imam to say the Taslim after the prostration of forgetfulness in order to make up what he missed, or should he stand up immediately?

If the latecomer catches the Imam in one rak'ah or more, he performs the pre-salaam prostration of forgetfulness (sujud al-sahw al-qabli) with him. However, if he catches less than one rak'ah, the well-known opinion in the Maliki madhhab — the saying of Ibn al-Qasim — is that he does not prostrate with him. In all cases, the latecomer does not stand to make up what he missed until after the Imam's salaam; because it is established in the madhhab that the latecomer does not stand to make up what he missed except after the Imam's salaam. And Ibn al-Qasim preferred that the latecomer stand after the Imam's salaam from the post-salaam prostration of forgetfulness (sujud al-sahw al-ba'di).