Comment 10 for bug 1740666

Confirmed on Ubuntu 20.04 - kernel 5.4.0-135
The behaviour exits for about the last 5 kernel updates - but also a weak bios battery (wrong hw clock after resume) can be the reason for the problem.
The time sync happens only after several minutes.

Active/Running Service: systemd-timesyncd.service
(Disabled Service: systemd-networkd.service - netplan deactivated due to network problems)

Output of timedatectl immediately after resume:
               Local time: Mi 2023-01-04 04:46:17 CET
           Universal time: Mi 2023-01-04 03:46:17 UTC
                 RTC time: Mi 2023-01-04 03:46:18
                Time zone: Europe/Vienna (CET, +0100)
System clock synchronized: yes
              NTP service: active
          RTC in local TZ: no

Suggested solution:
Forcing an immediate time sync after resuming from hibernation.