The Prophet ﷺ said, "Pray before the Maghrib (compulsory) prayer." He (said it thrice) and in the third time, he said, "Whoever wants to offer it can do so." He said so because he did not like the people to take it as a tradition.  

عَنِ النَّبِيِّ ﷺ قَالَ صَلُّوا قَبْلَ صَلاَةِ الْمَغْرِبِ قَالَ فِي الثَّالِثَةِ لِمَنْ شَاءَ كَرَاهِيَةَ أَنْ يَتَّخِذَهَا النَّاسُ سُنَّةً  

I went to ʿUqba bin 'Amir Al-Juhani and said, "Is it not surprising that Abi Tamim offers two rakʿat before the Maghrib prayer?" ʿUqba said, "We used to do so in the lifetime of Messenger of Allah ﷺ." I asked him, "What prevents you from offering it now?" He replied, "Business."  

عُقْبَةُ إِنَّا كُنَّا نَفْعَلُهُ عَلَى عَهْدِ رَسُولِ اللَّهِ ﷺ قُلْتُ فَمَا يَمْنَعُكَ الآنَ قَالَ الشُّغْلُ