I haven't seen Avatar 2, but this or something similar is something I notice all the time in films on DVDs, especially those originally for TV: the camera will

I haven't seen Avatar 2, but this or something similar is something I notice all the time in films on DVDs, especially those originally for TV: the camera will cut to a long shot and everything becomes weirdly smooth until the camera cuts back again. Whether it's due to a change in film speed, frame rate or something else I can't work out, but I would imagine that these long distance shots are in fact library footage spliced into the film.