Earlier quoted context omitted.
The article points out that you can set hours when Windows will update.
The article fails to mention that rebooting is interpreted as a free "you can update my computer now" card.
Then one day windows realizes, holy smokes, we have to install those updates now! And proceeds to restart your computer regardless of your update preferences, typically right in the middle of your business day.
Changing the updates to install on shutdown is slightly more challenging than disabling updates (it is hidden in an option about power settings on boot). So guess what people do?