T42G NTP time sync issues

[kevinwalkerca]

I have three sets of T42G phones:

Set 1 (10 phones): Firmware version 29.71.0.121
Set 2 (2 phones): Firmware version 29.72.0.46
Set 3 (1 phone): Firmware version 29.72.0.55

All have the following time settings:
DHCP Time = Disabled
Primary Server = us.pool.ntp.org
Secondary Server = cn.pool.ntp.org

The issue is that all the phones (except one in Set 2) show the same incorrect time. The time is slow by 3.5 minutes. The one phone in Set 2 is exactly the same as a radio sync'd clock I have.

I have set one of the incorrect time phones "Manual=Enabled", then changed the time to something completely wrong, then changed it back "Manual=Disabled" and the time jumps back to being off by 3.5 minutes.

I have tried different NTP servers and all have the same result. The one phone shows the correct time and all others are off by 3.5 minutes.