Q: Are you running TrueNAS virtualized or bare metal?
TrueNAS SCALE uses chronyd daemon for time sync
journalctl | grep chronyd
chronyc sources -v
Conf file is located /etc/chrony/chrony.conf
You have to uncomment the following line to enable statistics
#log tracking measurements statistics
Then use the following CLI to restart the chronyd daemon
service chronyd restart
Note: if you make subsequent changes via the System → General → NTP Servers it will over write the conf file.