I’m experiencing a reproducible issue with automatic date/time synchronization on macOS 27.0.1.
When “Set date and time automatically” is disabled, the Mac keeps the correct date (October 7, 2026). Manual synchronization also works correctly:
sudo sntp -sS time.apple.com
Both time.apple.com and time.euro.apple.com return the correct time.
However, as soon as I enable Network Time using System Settings or:
sudo systemsetup -setusingnetworktime on
the system clock immediately jumps back to November 15, 2024. I reproduced the issue on two completely different Internet connections, so it does not appear to be network/router-specific.
Logs from timed show that the problem occurs inside the automatic time synchronization path. When Network Time is enabled, TMTimeSynthesizer first sets the system clock to November 15, 2024:
Setting system time to Fri Nov 15 12:24:32 2024 from TMTimeSynthesizer
adjust,-59689167.400401711,success,1
timed then successfully contacts Apple NTP servers over UDP 123 and receives the correct time:
Received time Wed Oct 7 09:43:59 2026±0.09 from "NTP"
However, that correct NTP time is rejected:
TDTF,RejectATime,...innv,59689167.405555,...source,NTP
TDTF,RequestFastTime,Reject,...source,NTP
So the apparent sequence is: Network Time enabled → TMTimeSynthesizer restores an incorrect 2024 time → Apple NTP returns the correct 2026 time → timed rejects it because of the ~59.7M-second difference.
Manual sntp bypasses this behavior and immediately restores the correct date. I also already tried removing /var/db/timed/com.apple.timed.plist and rebooting, but the issue persists.
Could you please advise how to safely reset/reinitialize the persistent state used by timed / TMTimeSynthesizer, or confirm whether this is a known issue in macOS 27.0.1?