When a Jaspersoft report has Date input controls that are optional( date doesn't need to be entered), why doesn't the report return any data or less data than expected?
For PPM out-of-box JasperSoft based reports.
When a Date input control is not mandatory, by design it will default to using a relative date. If the input control is "Start Date" and is made "optional" it will use this month's Start date as the relative date. This is done to ensure that the Report server doesn't hit performance issues due to too much data being returned. This is the reason why most reports using FACTS tables instead of summary data will have input controls for dates being set up as mandatory.
If needed, you can take a report's existing query and redesign it to adapt it to your needs.