In the last 2 days I have updated to 14393.187 on 2 Tablets, 7 Desktops and 7 Notebooks without having operational problems, have only my wife's Notebook left to do. On 1 of the Tablets and 2 Notebooks I did use the downloaded file to manually start the update, most likely the Wi-Fi connections were just weak enough to not let the download complete using Settings, Update and security feature. Or maybe I was just 'lucky' enough to hit a slow period connecting to the server.
According to the folks at Portable Update software, the program will only run on Windows 10 build 10586, which will not do me any good.
So have we concluded that it's most likely server choke that has caused our "stuck" downloads?