Material Inventory Balance migration

Hello,

I am running into an issue with the testing of migration of material inventory balances.

The date defined in the app "Define Settings for Legacy Data Transfer" is set to 7/31/2019. All financial balances have been posted or in the process of being posted on that key conversion date. However, during UAT of other functionalities, the MM closing period has been moved so that the current period is 2019/09 and prior period is 2019/08.

As a result when we try to load the material inventory balances, we get the error "Posting only possible in period 2019/09 and in period 2019/08 in company code XXXX"

I tried leaving document date empty, set to 7/31/2019 or to 8/31/2019 with same result. At the same time it doesn't seem possible to change the date in "Define Settings for Legacy Data Transfer".

Did anyone else run into a similar issue? and how did you resolve?

Thanks

Lorenzo