Affected Products: 
Single function: CS720, CS725, CS820, C4150, C6160
Multi-function: CX725, CX820, CX825, CX860, XC4143, XC4150, XC4153, XC6152, XC6153, XC8155, XC8160, XC8163
NOTE :
An x denotes any number within a given printer model series.
Issue Description:
A 12-hour time format appears on the printer’s control panel even when the printer's time format is set to 24-hour from the printer’s embedded webserver ( EWS).
Here are sample screen shots for a comparison:
24-hour format set on the printer settings
12-hour format appearing on the printer’s control panel
Solution:
The issue was found to occur in version 4.5.3 for the Display customization app.
To resolve this issue, this app needs to be updated to version 4.5.3.1 or higher, which is available on the Lexmark virtual solutions center ( VSC).
Still Need Help?
Have the following available when calling Lexmark Technical Support;
Printer model(s)
Printer serial number
Name and version of the solution
LEGACY ID: SO8171