Ata' bin Abi Rabah (may Allah have mercy on him) said: I prayed the Maghrib prayer behind Ibn al-Zubayr (may Allah be pleased with them both). He gave the salam after two rak'ahs, then stood up to touch the Black Stone, so the people said "Subhan Allah". He came back, completed the rest of the prayer, and performed the two prostrations of forgetfulness (sajdat al-sahw). I asked Sayyiduna Ibn Abbas (may Allah be pleased with them both), and he said: "How excellent his father is (meaning: how well he did)! He did not deviate in the slightest from the Sunnah of his Prophet (peace and blessings be upon him)."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 11436