Muawiya prayed witr with a single rakah after the Isha prayer, and a freed slave of Ibn Abbas was present. He went to Ibn Abbas and reported this. Ibn Abbas said, "Leave him alone, for he was a companion of the Messenger of Allah ﷺ."
حدثنا الحسن بن بشر حدثنا المعافى عن عثمان بن الأسود
أوتر معاوية بعد العشاء بركعة وعنده مولى لابن عباس فأتى ابن عباس فقال دعه فإنه قد صحب رسول الله ﷺ