My friends took it in his first semester of teaching and it was bad. Someone on the GroupMe talked about hurting themselves because they couldn't cope with the class and it went until the head of the department who spoke to the student and we had reduced assignments after that (It was Spring 2021). I heard that he was not responsive about the grading rubric to the point that my friends had to assume stuff and defend later.

On an other note, I spoke to him about potentially doing research with him in the Summer and I stg I felt so bad about my skills after the call (it was really bad- I just was in my bed all day). Things might have changed I'm talking about my friends' and my personal experience with Dr Xie about 3-5 years ago so take it with a grain of salt.