A wording by Ahmad has:

Abu Rukana divorced his wife with three pronouncements, in one sitting. Then, he was grieved about her and Allah's Messenger (ﷺ) told him, "They (the three pronouncements) are reckoned as a single (utterance of divorce)." [The two Ahadith have Ibn Ishaq, in their chains of narrators, and his reliability has been questioned].

وَفِي لَفْظٍ لِأَحْمَدَ : { طَلَّقَ أَبُو رُكَانَةَ اِمْرَأَتَهُ فِي مَجْلِسٍ وَاحِدٍ ثَلَاثًا , فَحَزِنَ عَلَيْهَا , فَقَالَ لَهُ رَسُولُ اَللَّهِ ‏- صلى الله عليه وسلم ‏-" فَإِنَّهَا وَاحِدَةٌ } وَفِي سَنَدِهَا اِبْنُ إِسْحَاقَ , وَفِيهِ مَقَالٌ [1]‏ .‏