Jami` at-Tirmidhi 384
جامع الترمذي#384HasanAbu Rafi narrated that :He passed by Al-Hasan bin Ali while he was performing Salat and he had gathered his locks at the back of his head, so he (Abu Rafi) undid them, and Al-Hasan turned to him angrily. He said: "Resume your Salat and do not be angry, for indeed I heard Allah's Messenger (S) saying: 'That is the seat of Ash-Shaitan
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Ahmad Muhammad ShakirHasan
Al-AlbaniHasan
Bashar Awad MaaroufHasan
Zubair Ali ZaiIsnaad Hasan
In-book reference: 2:236