I've commented on a similar thing previously—

I worked for a while with some older Vietnamese refugees who were largely self-taught electrical engineers. They used to tell me how they'd dream about the circuits in these high-watt lighting ballasts they were fixing. One tale specifically had them trying to find a fix over the course of a week, only to dream up the solution and come in the next morning to repair the gear in minutes.

I've definitely dreamed up solutions to software bugs and architecture problems myself.

I've never really dug deeply into why, but it's fascinating.