Shu'bah (may Allah have mercy on him) said that al-Hasan (may Allah have mercy on him) did not hear from Samurah (may Allah be pleased with him), and this is also the position of Yahya bin Ma'in (may Allah have mercy on him). Ali bin al-Madini (may Allah have mercy on him) said that al-Hasan's (may Allah have mercy on him) hearing from Samurah (may Allah be pleased with him) is established.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الجنايات / 15947