In the French high school and university system, when students write an essay about a precise topic (e.g. "Is discussing renouncing violence?", Bac 2021), and the content of the essay is judged as not treating this precise topic (resulting in general for the misunderstanding of the topic by the student), the essay is said to be "hors sujet" ('off topic').

(1) Is there an exact same expression in English, with a similar usage (in terms of contexts of use and frequency of use)?

Or is "hors sujet" a Franco-French expression, with no exact parallel in Anglo-saxon countries?

(2) How to best translate the French academia-related expression "hors sujet" in English?