Despite Judge Engoron's critical role, Mr Trump was combative on the stand. He took direct aim at the judge, leading to some heated exchanges, and drew his rebukes for airing broad grievances when they were not directly relevant to the question.
"It does seem completely counterintuitive. Especially when the judge is going to be the finder of fact and law," says Kevin McMunigal professor of criminal law at Case Western University.... "I think he is trying to goad the judge into doing something he can argue on appeal shows prejudice on his part," Prof McMunigal said. "Maybe he makes a comment they can use to support a bias case later."
https://www.bbc.com/news/world-us-canada-67340454
"It does seem completely counterintuitive. Especially when the judge is going to be the finder of fact and law," says Kevin McMunigal professor of criminal law at Case Western University.... "I think he is trying to goad the judge into doing something he can argue on appeal shows prejudice on his part," Prof McMunigal said. "Maybe he makes a comment they can use to support a bias case later."
https://www.bbc.com/news/world-us-canada-67340454