When a report is scheduled with input parameters that return an empty report in Advanced Reporting, the email goes out to the recipient even when the "Do not send emails for empty reports" is selected during the scheduling activity.
Clarity engineering reviewed this with Jaspersoft and concluded that this is working as designed and raised an enhancement for the "Do not send blank email" feature to work for blank pages. Jaspersoft Enhancement ID= JS-29982. By design, the emails only trigger by the main dataset being empty, and when the report attribute returns has no pages. This is when the attribute 'whenNoDataType=NoPages' is returned.
The report attribute 'whenNoDataType=NoPages' means that the generated document will have no pages in it.
Clarity default reports return a single blank page.i.e.'whenNoDataType=BlankPages'. The default reports also appear to have bands that is designed to return "no data found". So there can then be blank pages in Clarity reports and hence emails will trigger for reports that are scheduled.
Clarity 14.2 onwards
Write custom reports that can adapt to the logic where the report returns 'whenNoDataType=NoPages'.
Reference "Do not send emails for empty reports" - how to make it work when sub Dataset is empty on Jaspersoft Communities.