This warning occurs when a system description is overridden due to duplicate declaration.
%s %s - '%s' - System description type- Description name.
%s(%d) - previous declaration(Line number).
Either rename the event if same name was used by mistake or remove the declaration if previous declaration should be executed.
Example
[System: Events]
CMPStateChangeLoad : Load Company : TRUE : Call : CMPStateNamechange
In the above example, the system event CMPStateChangeLoad is a duplicate declaration. Hence the message warning T0016: Duplicate description name System Events - 'CMPStateChangeLoad' - overridden. src\company\company.500(720) : was the previous declaration. appears.
The code is corrected by renaming the system event.
[System: Events]
MyCMPStateChangeLoad : Load Company : TRUE : Call : CMPStateNamechange