W52H time display setting reverts to 24 hour

[Yealink_Peter]

Hello Steve,

Does all the 7 handsets revert to 24 hour format, or just some?
Please check whether you have configured auto-provision (as below figure1).
The default time format can be defined by provision file (code as below figure2), if auto-provision working, phone will automatically update configuration in interval time. In other words, if it defined format as 24 hour, phone will revert it to 24 hours from 12 hours when provisioning even though you didn't change the time on handset manually.

thanks.
Peter