I am not sure if anyone has brought this to your attention:
In the directions for creating the calculation for the Baseline Forecast line item, It is asked that for the FY21 periods to use the FY20 "Initial Demand Forecast" (see screenshot below). The explanation in the parenthesis as well as the example below it, identifies this calculation as the "Default Forecast".
I think is because you're using the baseline forecast plus growth rate in the OFFSET formula. I've used the final forecast instead, and it seems to work for F21, because the final forecast for 2020 is the baseline for 2021 Hope it works for you