GRPs / Forecast values are incorrect
In case of wrong GRPs / Forecast values, a probable cause is that several forecast folders were imported for a single period.
Go to GeneralSettings > Ctrl. Values Marketplace > Forecast/Folder.
Set the current folder to Priority '1' (all other folders must have a higher priority), save the record, and then click on 'Apply Forecast'. The values from this folder will be adopted.