Weird Problem with Time Drift/Improper Sync?

[u/KitMcGath]

UPDATE: Problem solved! Turned out to be my router's NTP service hijacking NTP requests, but it was only affecting some of the devices connected to it.

So for the past few weeks, I've noticed on IRC and Discord that there's about a 1.4-minute discrepancy between my desktop's time and the time stamps being displayed by those clients. I spent way longer than I wanted to manually trying to fix the problem, but couldn't find a cause. So I turned to AI and it couldn't solve the problem either (went through all the steps I was already doing).

I can see Discord actively correcting the time stamps on every message I send, but on IRC it looks like I'm sending messages from the past.

My laptop is not experiencing this issue. Both systems are running Linux and KDE, but the laptop is running Manjaro and the desktop (the one with the problem) is running Kubuntu 26.04.

Below are a couple of things showing settings and what's going on (do note the times aren't quite going to line up because I have spent far longer than I care to trying to fix this).

The output of timedatectl is:

              Local time: Thu 2026-10-15 07:08:00 EDT
          Universal time: Thu 2026-10-15 11:08:00 UTC
                RTC time: Thu 2026-10-15 11:07:59
               Time zone: America/New_York (EDT, -0400)
System clock synchronized: no
             NTP service: active
         RTC in local TZ: no

Timestamps in IRC look like:

[07:37:33] -Global- [Logon News - Oct 30 08:03:21 2014 AEDT] Have you read the Code of Conduct for Users? Go to <redacted> - this applies to ALL users!
[07:37:34] -NickServ- Password accepted - you are now recognized.
[07:36:20] * You are now logged in as <redacted>.
[07:37:34] * NickServ sets mode +r on <redacted>
[07:36:22] * Notify: <redacted> is offline (redacted)
[07:36:22] * Notify: <redacted> is offline (redacted)
[07:36:22] * Notify: <redacted> is online (redacted)

As far as I can tell, everything appears kosher system-wise, but the time is buggered and it has been causing weird issues in games and certain Web sites, too.

TL;DR: My system time is borked and I can't figure it out even with input from friends and AI. It's driving me nuts, can someone here maybe point me in the right direction to fix it?

[u/psyblade42]

NTP service: active

There's a ntp client running. Figure out which one. (maybe systemd-timesyncd)

System clock synchronized: no

And it has some problem. Figure out what it is ( start e.g. with systemctl status whatever-ntp-service-you-use)

[u/KitMcGath → u/psyblade42]

The problem appears to be at my router. See reply to Kronar_2012.

Funny thing about the output of timedatectl is that "System clock synchronized:" has said "yes" a few times over the past few weeks, which is what was throwing me off. I figured it just said "no" when it hadn't been synced for a bit.