When displaying date fields from a query, the BIRT report is displaying one day before, e.g., 06/02/2015 shows 06/01/2015.
Legacy Date Only fields in the application are stored in the back-end database as Date and Time format, where the time is set by default to 00:00:00, as it is not used in the front end. The BIRT reports interprets this as the day before (midnight), while TRIRIGA displays this as the current day (zero hour).
To diagnose the problem, run a query directly to the database and check if the Date Only field also contains the time stored with it. Observe if the time is 00:00:00. To resolve the problem, update the records by adding one hour to the back-end database fields, i.e., modify fields from a format of 99/99/9999 00:00:00 to 99/99/9999 01:00:00. The BIRT reports will now consider the day as the same as the front-end TRIRIGA application.