The date time is directly obtained from NTP server. It gets UTC time, and the actual time displayed on the web interface depends on your web browser — the web browser uses the UTC time from OpenGarage combined with the local time zone to display local time. The only thing I can think of is if one of your OG is not getting response from NTP server. But I don’t know how that’s possible — it’s connected to your WiFi router, it looks like you are able to access it (albeit it’s slow), so I can’t think of any obvious reason why it won’t receive response from NTP server. Perhaps your router is blocking the packets for some reason?