Question:

When should a person in a jama’ah stand if they missed rakahs? Should it be after the first tasleem (done) to the imam’s right or should they wait until both are made?

Answer:

That’s a matter of difference of opinion between the scholars based upon if the second tasleem is merely a sunnah, or a waajib/pillar like the first tasleem. However, it is best to be cautious and on a safe side. Therefore (one should) try to not get up except after the Imam complets both tasleems and Allah knows best.

~ Abu Fajr AbdulFattaah bin Uthman