1. Remove the Time range and apply the normal timescale to the entire module.
2. Formula should be just " DAT03 Historic Volumes'.'Offset Volumes for 1st Forecast Year'" as you would have used OFFSET and IF ELSE statement in the DAT03 Historic Volumes module. You don't need to write it again in DEM03 module.
There wont be any values as you are trying to pull FY19 Values into FY20 as baseline. When you have FY20 historic values you will see FY21 values in this module. But to me you are good to go & don't need to see FY21 values.
Re: DEMO 03 Demand Forecast. Baseline Forecast formula
Used below formula, now data showing for FY21:
IF 'SYS01 Time Settings By Week'.'1st Forecast Year?' THEN 'DAT03 Historic Volumes'.'Offset Volumes for 1st Forecast Year' ELSE IF 'SYS01 Time Settings By Week'.'2nd Forecast Year?' THEN OFFSET(Final Forecast, -52, 0) ELSE 0
PS: I tried earlier the same formula, Some reason, data was not populating in FY21, but now its showing..