وَمَضَوْا إِلَى وَجْهِ الْعَدُوِّ، وَجَاءَتِ الطَّائِفَةُ الْأُخْرَى، وَصَلَّوْا رَكْعَةً وَسَجْدَتَيْنِ بِقِرَاءَةٍ، وَتَشَهَّدُوا وَسَلَّمُوا
Translation: The first group goes back to guard, and the second group returns to perform one rakah with recitation and two prostrations, then recites tashahhud and says salam.
The second group joined after the imam’s first rakah and is therefore a masbuq. Its missed first rakah is completed with recitation.
Both groups finish two rakahs, but recitation differs in the rakah each later completes.