Advanced Predictions - Observation / Issue

Summary:

I was trying out Advanced Predictions and seems like it doesn't work if the historical data is at parent level.

Content (please ensure you mask any confidential information):

I was trying out Advanced Predictions and seems like it doesn't work if the historical data is at parent level.

Source and Target both are same ASO cube.

Historical Data is at top level

Entity1 (level0)→All Legal Entities→All Brand→PTD→All Customer→Actual

Future Data is at bottom level as we cannot input at top level
Entity1 (level0)→Default Legal Entity→Default Brand→PTD→Default Customer→Forecast

I have only one driver.