I get these often and I wouldn’t define them as third person but more “non-person”. To me first person dreams are where I’m watching it through my eyes and Thurs person would be watching myself as I do things (like third person video games). Not even being in the dream, just a mind movie as you called it, seems like another level removed.

I wonder how much the amount of movies and video games around these days has changed this - whether dreams in the past would have only been first person because that’s the only thing people had experienced.