My dad's computer tried upgrading to 1809. It failed. It then tried again, but refused to do any of the work on reboot. So it's sat on 1803, but with a message saying reboot pending. It absolutely won't install the new OS version. I've tried deleting the software distribution folder, all sorts of stuff to no avail.
Come on Microsoft! At least it hasn't hosed the machine I suppose, small mercies.