Date gives back wrong second count, 3600 seconds off

[Hannu E K N]

In my opinion, the required '1970-01-01 **01**:02:18' below is wrong.
The answer should be 3600 more seconds.

Note: **02:18 is 138 seconds.**

$ man date
...
%s seconds since 1970-01-01 00:00:00 UTC
...

$ date +%s -d'1970-01-01 01:02:18'
138

$ date --version
date (GNU coreutils) 8.30
Copyright (C) 2018 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

Written by David MacKenzie.

$

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: coreutils 8.30-3ubuntu2
ProcVersionSignature: Ubuntu 5.13.0-40.45~20.04.1-generic 5.13.19
Uname: Linux 5.13.0-40-generic x86_64
NonfreeKernelModules: nvidia_modeset nvidia
ApportVersion: 2.20.11-0ubuntu27.23
Architecture: amd64
CasperMD5CheckResult: skip
CurrentDesktop: ubuntu:GNOME
Date: Sun Apr 24 15:12:14 2022
SourcePackage: coreutils
UpgradeStatus: No upgrade log present (probably fresh install)

[Hannu E K N (hannu-n)]

Corrected output:

$ echo $(( 3600 + $(date +%s -d'1970-01-01 00:02:18') ))