Depending on how and where you acquire your devices, they might come with a Windows build which have the Time Zone set to Pacific Time (UTC -7). Devicie, by default, enables the Windows service “Auto Time Zone Updater” which automatically adjusts the device time zone based on location information from the Windows Location APIs. That service works on an estimation based on information available like GPS, Wi-Fi, Cell Towers and IP Address.
When this service is enabled (at the time of the user enrolment) the service status is changed from Disabled to Automatic (Trigger Start). An automatic time sync should trigger the time zone updater service. Time syncs occur every 9 hours by default. Also, a windows restart should trigger time sync and subsequently time zone update.
When a new device that is configured to Pacific time is deployed, the time might be out of sync for up to 9 hours or until the device is restart (granted that the service “Auto Time Zone Updater” is setup as Automatic (Trigger Start) and not disabled.
If the time sync in not working as expected, the device may be setup as a hybrid device and connected to your local Active Directory. Hybrid joined devices will always sync time from domain controllers as their primary source.
Check with your internal IT department to confirm your local AD is set with the correct time and that your device is able to communicate with the server.
You might also need to check and confirm the proxy is not blocking the communication between your device and your local Active Directory.