Ata (may Allah have mercy on him) said that Tariq bin al-Muraqqi' freed the members of several households of the people of Yemen as sa'ibahs, and they died leaving more than ten thousand. This was mentioned to Sayyiduna Umar (may Allah be pleased with him), and he ordered that it be given to Tariq or to Tariq's heirs.
Imam al-Shafi'i (may Allah have mercy on him) said: It is I who had this doubt in the hadith.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الولاء / 21479