Ibn Umar said, "I saw the Messenger of Allah ﷺ on the pulpit. When I saw him, I hurried into the mosque and sat down, but I could not hear anything until he descended. So I asked the people what the Messenger of Allah ﷺ had said, and they replied that he had forbidden using gourds and pitch-coated vessels for steeping drinks."
حدثنا سفيان حدثنا يحيى بن سعيد
ابن عمر رأيت رسول الله ﷺ على المنبر فلما رأيته أسرعت فدخلت المسجد فجلست فلم أسمع حتى نزل فسألت الناس أي شيء قال رسول الله ﷺ قالوا نهى عن الدباء والمزفت أن ينتبذ فيه
Its chain of transmission is sahih, but it belongs to the category of narrations in which a companion relates something from the Prophet without having heard it directly from him. Ibn Umar plainly stated that he did not hear this from the Messenger of Allah, but rather some of the companions present at the time informed him of it. Malik related it likewise, at 3:55, from Nafi. Muslim related it at 2:128, through the route of Malik and other routes, from Nafi. It has already passed at 4425, also through the route of Nafi, from Ibn Umar, that the Messenger of Allah forbade it, without mentioning whether he had heard it himself or not.Muslim related something similar at 2:129, through the route of Ibn Zubayr, who heard Ibn Umar say, "I heard the Messenger of Allah forbid the clay jar, the gourd vessel, and the tar-coated vessel." So it appears that Ibn Umar did not hear it the first time, but then heard it from the Messenger of Allah on another occasion, and so he related both instances according to each case.Such reports, in which a companion relates something without having heard it directly from the Prophet, are a valid proof in every case.