I heard Ibn Abbas giving a legal verdict regarding currency exchange, so I issued verdicts based on it for some time. Then I met him and found that he had retracted his position.I asked him, "Why?"He replied, "It was merely an opinion I had formed. Abu Saeed Khudri narrated to me that the Messenger of Allah ﷺ forbade it."
حدثنا وكيع حدثنا سليمان بن علي الربعي قال سمعت
سمعت ابن عباس يفتي في الصرف قال فأفتيت به زمانا قال ثم لقيته فرجع عنه قال فقلت له ولم فقال إنما هو رأي رأيته حدثني أبو سعيد الخدري أن رسول الله ﷺ نهى عنه
Its isnad is sahih. Sulayman bin Ali Rubai, Abu Ukashah, is trustworthy, and likewise Abu Jawza, Aws bin Abdullah Rubai. The hadith has already been mentioned at 9964.