what bothers me is that one person stated already я посмотрел (perfective) and then the other person replies... NOT using the perfective??? That seems just weird to me but if it's something I have to accept I guess I just have to accept it. Why would he not reply using the same verb form as the style and information the verb carries has aleady been dictated by the first speaker, I would have thought.
But when you translate it to English, you probably also use two different tenses:
- I have already watched this movie.
- When did you watch it?
Does it seem weird to you?