Question 197) - What should a Munfarid do if he completed a Rak'ah of Zhuhr or 'Isha with the Sujud and congregational Salah commences?

This part is not in al-Quduri. i have added from Fat-hul Oadir and-Fatawa al-Hindiyah

(i.e. actual Salah of the Imam commences, not merely Iqamah. In that case if the Munfarid did not complete the Rak'ah with Sujud, he completes the two Rak'at. There is no difference amongst our 'Ulama about this. ~an-Nihayah~ prefer to al-Fa~awa al-Hindiyah 119/1).

A: He adds another Rak'ah and joins the Jama'ah.

~ al-Quduri ~