If I remember right it never went off of 8% but if you open task manager and look under performance at your internet connection or you go to app history and look at the amount downloaded you can see it is still downloading. I watched that the download progressed in task manager until it finally quit so then I manually rebooted my computer and then it finished downloading and installed normally. I think I waited way longer than needed before rebooting.
I had this same problem on both of my dev channel non compliant computers that are now on Windows 11 so it does work