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 from the misunderstanding of the topic by the student), the essay is said to be "hors sujet" ('off topic').
Being off-topic ("être hors sujet") is a very serious issue, and has normally for consequence a very low grade (from 2/20 to 6/20), no matter the quality of the essay.
(1) Is there an equivalent expression in English, i.e. an expression with a similar usage (in terms of contexts of use and frequency of use)?
Or is "hors sujet" a Franco-French expression, with no good equivalent in AngloEnglish-saxonspeaking countries?
(2) How to best translate the French academia-related expression "hors sujet" in English?