Why is the request status description different in various pages for the same request?

Request status may come from the RequestStatus table (e.g. Related Requests sections in various pages such as Project, Customer, Request, the status name in the request history, ...etc) or from the workflow state name (e.g. Request status in request dialog, status drop down). 

You can change the description of the status code in RequestStatus table, in order to match the status name used in workflow definition.