NTP users are strongly urged to take immediate action to ensure that their NTP daemons are not susceptible to being used in distributed denial-of-service (DDoS) attacks. Please also take this opportunity to defeat denial-of-service attacks by implementing Ingress and Egress filtering through BCP38.
ntp-4.2.8p15 was released on 23 June 2020. It addresses 1 medium-severity security issue in ntpd, and provides 13 non-security bugfixes over 4.2.8p13.
Are you using Autokey in production? If so, please contact Harlan - he's got some questions for you.
NTP Startup Issues
The usual perspective when starting NTP is that there are two "startup conditions", cold-start (boot) and warm-start (restart).
Related Topics: NtpStartupStepChoices
At cold-start, we don't know how long the machine has been "off" and we may not have a good idea of any needed frequency or offset correction.
No services requiring monotonic time are running.
At cold-start, it is expected we can safely make any changes to system time that we want.