system_clock_sync_state warning on Synology NAS

I am running netdata across 3 nodes (1x rpi, 1x small ubuntu server and 1x Synology DS920+).

I am having an issue where the Synology NAS is always showing a warning against the system_clock_sync_state metric. I have checked that the NAS is using ntp (see screenshot)
Screenshot 2023-11-04 093111

What else can I check? Is it an erroneous warning?

All netdata nodes running in docker containers using “v1.43.0-148-nightly3”.
Synology DSM is Version: 7.2-64570 Update 3

This is still happening - any ideas anyone?