It is narrated from Hazrat Ya'la (may Allah be pleased with him) that I saw the Prophet (peace and blessings be upon him) performing idtiba' (uncovering the right shoulder) between Safa and Marwah in a Najrani cloak while in the state of ihram.
Hadith Referenceمسند احمد / مسند الشاميين / 17955
Hadith Gradingحکم دارالسلام:حديث صحيح، وهذا إسناد ضعيف، عمر بن هارون متروك الحديث