I would like to ask you concerning a situation I was a few years back.
I was an unofficial intern at a research institution. The aim of the internship was to study and search for new methods from a field that was unfamiliar to me or my supervisor and to check how it could be used in my supervisor's field. During this internship, my supervisor asked to study an article that was put for submission, and to write some kind of peer review report on it. I was unfamiliar with the topic, and the supervisor was unfamiliar with one of the topics (it was an article that used a combination of two fields). I did it, but eventually realized that it didn't seem to be ethical, as you need an expert to conduct such work. I even wonder if it was legal.
The situation took place in EU.