[Machine] Abdullah bin Umar used to recite in all four units of prayer, in each unit, Surah Al-Fatiha and another Surah. Sometimes he would recite two or three Surahs in a single unit of the obligatory prayer. He would also recite Surah Al-Fatiha and another Surah in the two units of the Maghrib prayer. These details are mentioned in the narration of Ibn Bukair, and Al-Shafi'i did not mention anything specifically about the Maghrib prayer.  

أَنَّ عَبْدَ اللهِ بْنَ عُمَرَ كَانَ إِذَا صَلَّى وَحْدَهُ يَقْرَأُ فِي الْأَرْبَعِ جَمِيعًا فِي كُلِّ رَكْعَةٍ بِأُمِّ الْقُرْآنِ وَسُورَةٍ وَكَانَ أَحْيَانًا يَقْرَأُ بِالسُّورَتَيْنِ وَالثَّلَاثِ فِي الرَّكْعَةِ الْوَاحِدَةِ فِي صَلَاةِ الْفَرِيضَةِ وَيَقْرَأُ فِي الرَّكْعَتَيْنِ مِنَ الْمَغْرِبِ كَذَلِكَ بِأُمِّ الْقُرْآنِ وَسُورَةٍ سُورَةٍ لَفْظُ حَدِيثِ ابْنِ بُكَيْرٍ وَلَمْ يَذْكُرِ الشَّافِعِيُّ الْمَغْرِبَ