error in hours given by date -d @anyNumber

[Girod Valentin]

Configuration Information:
Machine: x86_64
OS: linux-gnu
Compiler: gcc
Compilation CFLAGS: -g -O2 
-fdebug-prefix-map=/build/bash-a6qmCk/bash-5.0=. 
-fstack-protector-strong -Wformat -Werror=format-security -Wall 
-Wno-parentheses -Wno-format-security
uname output: Linux valentin-Aspire-F5 5.11.0-46-generic 
#51~20.04.1-Ubuntu SMP Fri Jan 7 06:51:40 UTC 2022 x86_64 x86_64 x86_64 
GNU/Linux
Machine Type: x86_64-pc-linux-gnu

Bash Version: 5.0
Patch Level: 17
Release Status: release

Description:
    when using date -d @customNumber +%H,
    it returns 1 more hour that the expected hour.
Repeat-By:
    date -d @0 +%T
    returns: 01:00:00 (WHAT THE FUCK)
    excpected output: 00:00:00
    date -d @18130 +%T
    returns: 06:02:10
    expected output: 05:02:10
    (verification here: 
https://www.google.com/searchq=number+of+seconds+to+hour&oq=number+of+seconds+to+hour&ie=UTF-8)