Deepin is based on Debian unstable (Sid)Isn't Deepin OS based on Ubuntu? If you don't utilize unattended-upgrades, you can remove it, which should get rid of the message.
I did everything you said and i got the same message when i wanted to restart or shut down. So i went to my service list to see if i can find it in the list of services running and found it. It was enable to run at all times. So i disable it and set it up not to run. Now i don't get the message when i restart or shut down the computer.Do what @KGIII has suggested above, First.
Then, read what i have pasted below..The Unattended Upgrades installs security updates automatically in Ubuntu. This guide explains how to disable unattended upgrades on Ubuntu.ostechnix.com
Disable unattended upgrades on UbuntuTo disable unattended upgrades on Ubuntu and its derivatives, run:
$ sudo dpkg-reconfigure unattended-upgrades
Choose No and hit ENTER to disable unattended upgrades.
Disable Unattended Upgrades On Ubuntu
You can also remove it altogether if you don't want it anymore.
$ sudo apt remove unattended-upgrades
It doesn't remove any other software on your Ubuntu system, so it is safe to remove unattended upgrades package.
From now on, your Ubuntu system doesn't automatically download and install important updates. You have to manually download and install updates once in a while by using commands:
$ sudo apt update
$ sudo apt upgrade
The Unattended Upgrades feature is enabled by default and it runs at system boot without user's permission. This might be helpful for casual users who wants to keep their system up-to-date without user-intervention. But for testing systems, It is completely unnecessary, so I disabled it in all my Ubuntu VMs.