Musannaf Ibn Abi Shayba 4:777

Waki’ narrated to us, from Sufyan, from Ibn Jurayj, from al-Zuhri, from Sa’id ibn al-Musayyib; and from Sufyan, from Ibn Jurayj, from ‘Ata’: They both said: The one in I’tikaf does not attend a funeral, nor does he visit a sick person.