Long delay while rebooting after applying an automatic upgrade

Originally created by @intrigeri on #17026 (Redmine)

This got reported for the 4.0~beta1 → 4.0~beta2 upgrade. I don’t know yet if 3.x is affected.

User report:

The behavior that the first shutdown after the incremental upgrade takes
much longer was there again.
I pressed Esc and its one line which is constantly changing between:

(1 of 2) A stop job is running for User Manager for UID 112 ( x / 2 min)
and
(2 of 2) A stop job is running for User Manager for UID 1000 ( x / 2 min)

The x is counting up till 1 min 30 s then:
[ok] Stopped User Manager for UID 112.

and the shutdown process is going on.

On every other shutdown the whole shutdown process is done after a few
seconds but after an incremental update it takes minimum one and a half
minutes so i think at least after an upgrade the user should see that his
computer isnt done with shutting down after a few seconds.

Feature Branch: bugfix/17425-dont-propose-upgrading-to-running-version

Related issues

• Related to #14544 (closed)
• Related to #17313 (closed)