This behavior may be due to some idiosyncrasy in my System but Mojave did not reset the update preferences on my machine after a postponed install. I maintain the following settings:I'm sorry but that's just plain wrong on Apple's side (and clearly we've been here before). It does not matter how important the update is, I specifically don't have "automatically download updates" on, and force-downloading content to my computer is totally wrong! ...
- Automatically keep my Mac up to date - unchecked
- Check for updates - checked
- Download new updates when available - unchecked
- Install macOS updates - dimmed and unchecked
- Install app updates from the App Store - dimmed and unchecked
- Install system data files and security updates - checked
So, I manually requested the most recent Mojave update yesterday. I wasn't ready to install it when the download finished, so I hit "Later" and chose the wait-an-hour option. I was ready to run the updater before the hour had elapsed so I went to Apple Menu/About This Mac/Software Update and started the update myself.
After the update completed, the settings listed above were unchanged. As always, your milage may vary...