We're keeping a close eye on the "bouncing downloads" scenario.
It's has been seen previously when there was a high number of downloads hitting the server simultaneously. There was a big influx this morning from the Canary Channel release, but the number of users hitting this scenario seems to have subsided.
If folks are still hitting this, please do post up here or have them file feedback. We're digging into a few submissions already to see if it was a particular file or server endpoint that was common among those experiencing this.
I had one bounce earlier using Windows Update.
Now I just tried an update from 25314.1010 to 25324.1000 using the MS ISO file just downloaded.
It took quite a long time just checking for updates before finally taking off.
Now it is finally Installing.