Well, the "Windows Configuration Update (KB5030509)" that was installed when I enabled "Get the latest updates as soon as they're available" included a number of File Explorer improvements, but it didn't fix this bug. I left an Explorer window open but behind a maximized iTunes window as I sat nearby reading while listening to music, and within an hour, I glanced up and saw it had come to the front. My secondary monitor was showing the same Windows Spotlight wallpaper as when I started, so as I've said before, wallpaper changes are not a necessary condition. I'm not on a domain, so the group policy updates hypothesized to cause the problem aren't causing mine. This happened spontaneously, while I wasn't using the computer, though a couple of messages ago, I noted certain actions such as pressing the Start button on my keyboard seemed to cause it to happen immediately, though unreproducibly.
Again, my belief is that Microsoft will fix this whenever they get around to fixing it, and trying to find the cause at the user level is a lost cause. When I need to keep a File Explorer window open for an extended period, maybe because I've got a set of tabs I'm using during a lengthy operation, I'll continue minimizing it, as I don't believe I've seen one pop open from that state, and I recently did a 5 day experiment to try to confirm this, and it didn't happen.
