My school I’ve gone to being a private one, this has had always been a lot rarer, as people like that typically become faculty members of public schools, but long ago there was someone in my peer group with a teacher parent. Lots of Sharkboy and Lavagirl vibes there because the teacher/parent would go out of their way to comment on the classmate, single her out, and be wary of anyone who became friends with her. I remember whenever a test was to be given and graded, the parent/teacher would be absent.