I can't recall exactly the conditions, but do recall that occurring. I also have read that the brain "fills things in". Back fills so to speak.
If you think about a dream, are there really voices and such? You're probably experiencing something holographically somehow, and later when you "remember" it, the brain constructs it into something that makes sense to your mind.
One of the strangest dreams I remember is a dog was biting at me, my bed at the time was right against a wall. I kicked the dog .. actually kicking the wall in my sleep and waking me up.
But I know I've dreamt things that are happening in the waking world, into my dreams in real time as well.