Ata reported,

Ibn Zubayr was leading the Maghrib prayer and gave the salam after only two rakats, then rose to touch the Black Stone. The people said "Subhan Allah" to alert him.He asked, "What is the matter with you?"He then prayed what remained and performed two prostrations of forgetfulness.This was mentioned to Ibn Abbas, who said, "He has not departed from the Sunnah of his Prophet ﷺ."

حدثنا عبد الأعلى حدثنا سعيد عن مطر

عن عطاء

أن ابن الزبير صلى المغرب فسلم في ركعتين ونهض ليستلم الحجر فسبح القوم فقال ما شأنكم قال فصلى ما بقي وسجد سجدتين قال فذكر ذلك لابن عباس فقال ما أماط عن سنة نبيه ﷺ