This article provides a solution for manually adding section keys to a report.
You might see the following warning after trying to run Fix report:
Warning
This report section keys are not possible to fix automatically. You must add unique keys in sections manually by using Visual Studio.
Resolution
To remove the validation warnings, the placeholder LACRecId_DONOT_CHANGE must be added manually to fields in the report.
Additional information
Lasernet plugin does not support automatic fixing for reports that are based on a query rather than on DataSource class.