UC Version 15 Post Upgrade NTP Issue

[UCAdmin405]

Has anyone had any issues with NTP after upgrading to version 15? I just upgraded my test CER cluster from v14su3 to v15su1. I had an issue with the database not starting on the primary node after switching versions. But a reboot of the server fixed (started) the database. However, after switching the version and the second reboot I'm still getting the WARNING: NTP is Unreachable message (the NTP server is up and running and reachable). Running the 'utils ntp status' command returns "ntp is stopped". Running the 'utils ntp start' command returns "NTP is already running", and the restart command fails. The kicker is the 'utils diagnose test' command returns a pass for all the NTP related tests. I engaged TAC but I'm waiting for a response. While I'm waiting I went ahead and upgraded my PCD server from v14 to v15 as well. I'm experiencing the same issue with the exact same results I'm getting in CER. So to me it seems to be something with version 15 and the change from centOS to AlmaLinux since the same thing is happening both on CER and PCD? I'm at a loss and I haven't found anything in documentation regarding NTP issues. I figured I'd try my luck here and see if the community has seen anything like this before?

[mac-mcinvaille]

I have a similar yet different issue. We are already on v15. When I try to add two new NTP servers (only 2 defined today), the first one adds without issue. Even the second new one adds up until I have to restart. From then on I get NTP service is stopped. Even trying to force NTP to restart it remains stopped. The only thing I have been able to do is leave one old NTP and the one new NTP. I had this happen on both CUCM and CUC. These old NTP servers are going away soon. So far TAC has been as baffled as the rest of us.

Anyone here experience this by adding new NTP devices? They are the Linux version of Galleon and the first one works like a champ. 

[UCAdmin405]

Are both new NTP servers advertising the stratum? As @Roger Kallberg mentioned previously if both new servers aren't configured correctly to send stratum then it won't work successfully with the UC servers. I got the same issue regarding the stopped NTP and the root cause of that was the lack of stratum advertisement from the NTPd server in the packet capture I took. Can you confirm that the stratum is being received from the NTP server via a PCAP on your UC server?