I had an elaborate dream the other night involving a musical number and very detailed setpieces. And I remember in the dream thinking: this isn't how it was done before, before they did it like - Oh! now they're doing it right. This has happened before, where during the dream I can recall having had the dream in the past, or upon waking I recall having had the dream in the past.
It doesn't happen often, but is it unusual? Have any others experienced this? The dreams don't recur on successive nights, so it isn't related stress causing them to repeat. Often there are months or years in between recurrences.